Original Paper Phonetica 2013;70:298–322 DOI: 10.1159/000356628

Received: July 8, 2013 Accepted after revision: October 23, 2013

An Articulatory and Acoustic Study of the Fricative Clusters /sʃ/ and /ʃs/ in Catalan Daniel Recasens

Meritxell Mira

Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain

Abstract Electropalatographic and acoustic data for the fricative clusters /sʃ/ and /ʃs/ and the single fricatives /s/ and /ʃ/ in Eastern Catalan reveal that, while /sʃ/ undergoes regressive assimilation, /ʃs/ blends into an intermediate fricative or exhibits a twotarget realization. On the other hand, acoustic data for /ʃs/ in Western Catalan show that /s/ may assimilate to preceding /ʃ/ or undergo blending or a two-target realization depending on speaker and prosodic condition (no data are available for /sʃ/ in this dialect). Duration values for the two fricative clusters suggest that the assimilated outcome of /sʃ/ shortens down to the length of /ʃ/. A production-based account of the two sequences /sʃ/ and /ʃs/ in Catalan and other languages is proposed. © 2014 S. Karger AG, Basel

1. Introduction

© 2014 S. Karger AG, Basel 0031–8388/14/0704–0298 $39.50/0 E-Mail [email protected] www.karger.com/pho

Daniel Recasens Departament de Filologia Catalana Universitat Autònoma de Barcelona ES–08193 Bellaterra, Barcelona (Spain) E-Mail [email protected]

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This article is a contribution to the study of the phonetic realization of the consonant clusters /sʃ/ and /ʃs/ using data from Eastern Catalan (which is spoken in Eastern Catalonia around the Barcelona area and is considered to be the most prestigious Catalan dialect) and from Western Catalan (which is spoken in Western Catalonia around the Lleida area). Electropalatographic (EPG) data on linguopalatal contact as well as acoustic data will be recorded and analyzed for this purpose. As pointed out below, the clusters /sʃ/ and /ʃs/ have attracted the scholars’ attention in recent times because their realization depends both on the articulatory characteristics of /s/ and /ʃ/ and on the articulatory mechanisms involved in coproducing the two fricatives in a different order. Another reason for conducting this phonetic study is that languages and dialects may differ from each other regarding the direction of the intersegmental adaptation effects occurring in the two fricative consonant sequences of interest.

Before proceeding with the phonetic realization of the sequences /sʃ/ and /ʃs/, some general information about the articulatory and acoustic characteristics of the two lingual fricatives /s/ and /ʃ/ is in order [Ladefoged and Maddieson, 1996; Narayanan et al., 1995]. Regarding constriction location, /s/ is alveolar and more anterior or posterior depending on dialect, and /ʃ/ exhibits a more retracted postalveolar, postalveoloprepalatal or prepalatal constriction. Also, while the former fricative may be apical or laminal, the latter is articulated commonly with the blade and possibly the predorsum. The two consonants differ typically in sublingual cavity size, which is larger for /ʃ/ than for /s/, and in tongue dorsum position, which is higher for /ʃ/ than for /s/. Differences in front cavity size account for why the main spectral peak of the frication noise is higher for /s/ (typically at about 4,500–5,500/6,500 Hz) than for /ʃ/ (at about 2,300–4,500 Hz) [Jongman et al., 2000; Nartey, 1982]. The alveolar fricative /s/ has a more retracted constriction location and a more /ʃ/-like quality in Catalan (Eastern variety) than in languages like English, French or Italian, and consequently exhibits a larger front cavity size and a lower front-cavity spectral peak at about 3,500–4,500 Hz [Recasens and Espinosa, 2007]. As for the articulatory characteristics of fricative clusters, studies on English and French report an asymmetrical pattern of segmental adaptation in the consonant sequences /ʃs/ (which is found in English fresh soil and French la vache sort ‘the cow goes out’) and /sʃ/ (which occurs in English this shoe and French une mousse chargée ‘a loaded mousse’) [Holst and Nolan, 1995; Niebuhr et al., 2011; Niebuhr and Meunier, 2011; Nolan et al., 1996; Pouplier et al., 2011]. According to these studies, coarticulatory effects in these fricative sequences are triggered essentially by /ʃ/ and operate at the regressive rather than at the progressive level: thus, /sʃ/ undergoes typically regressive assimilation (i.e., a categorical change by which /s/ acquires the place of articulation of /ʃ/ throughout its entire duration essentially without exception), while /ʃs/ may be implemented through other production mechanisms besides progressive assimilation (i.e., the replacement of /s/ by /ʃ/), which will be referred to below. Categorical and highly systematic place assimilations in consonant sequences may be said to be ruled by the cognitive component of speech to the extent that they are not conditioned by the ongoing state of the articulators. It may also be the case, however, that the assimilated consonant is near-identical to the consonant triggering the assimilatory process while still keeping a residue of the original unassimilated gesture. These partial or gradual assimilations have been reported to occur, for example, in alveolar + velar sequences when C1 exhibits more or less regularly an imperfect alveolar closure and/or some contact fronting at the sides of the alveolar and palatal zones, as in English [Ellis and Hardcastle, 1999, 2002] and German [Kühnert and Hoole, 2004]. Instances of a residue of the alveolar gesture have also been found towards the onset of the sequence /s#ʃ/ under analysis in the present article [English: Holst and Nolan, 1995; Nolan, 1992]. The fact that place assimilations may operate gradually has led to the proposal advocated by Articulatory Phonology that assimilatory processes arise from large degrees of overlap between the articulatory gestures for consecutive consonants and are likely to occur in conditions which favor much gestural superposition, e.g., in fast speech and in word positions of little prosodic prominence [Browman and Goldstein, 1990, 1992]. Production data show, however, that, depending on language and speaker, place assimilations in consonant clusters may operate not only in a gradual fashion and Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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1.1 Articulatory Mechanisms for the Production of /sʃ/ and /ʃs/

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more or less often but may also be complete and occur almost systematically. Thus, the assimilation of /n/ to a following velar or labial stop may apply categorically as a general rule in Italian and Spanish [Farnetani and Busà, 1994; Honoroff, 1999], and completely, partially or not at all in English and German (see above references). In addition to segmental assimilation, two other adaptation mechanisms may be used by speakers for the realization of both clusters and, as referred to earlier, of / ʃs/ rather than of /sʃ/. First, gestural blending which can be characterized as a phonetic process by which gestural superposition gives rise to an intermediate realization between /s/ and /ʃ/ during the entire cluster except perhaps at the cluster edges, and takes place since the two lingual fricatives are produced with the same or close primary articulators [Browman and Goldstein, 1989; Recasens, 2006]. The intermediate fricative realization in question may be characterized as palatalized alveolar ([sj]). A second outcome is a two-target realization proceeding from the articulatory configuration of C1 to that of C2; in this case, while exhibiting some anticipatory (C1-to-C2) or carryover (C1-to-C2) coarticulatory effects, the two consonants show essentially the same realization as they do when flanked by vowels. Differences in the mechanisms of segmental adaptation between /sʃ/ and /ʃs/ explain why spectral measures (mostly center of gravity, COG) are more variable for /ʃs/ than for /sʃ/ in English and French [Niebuhr et al., 2011]. Within this scenario, the present article will investigate whenever assimilation, blending and a two-target realization operate in sequences of alveolar and palatoalveolar fricatives in Catalan using articulatory and acoustic data. It will also throw light onto the phonological or phonetic nature of assimilatory and blending processes by looking at whether the phonetic realizations of /sʃ/ and /ʃs/ are identical or intermediate with respect to those of the two simple fricatives, and also at how variable they happen to be across speakers and prosodic conditions. The study will also propose plausible explanations as to why the three production strategies operate the way they do. Along these lines, it looks reasonable to hypothesize that these strategies are associated with articulatory factors to a large extent. Thus, the reason why /ʃ/ prevails upon /s/ and, thus, /sʃ/ (also /ʃs/) yields [ʃʃ] rather than [ss] could be associated with a higher degree of lingual coarticulatory resistance for the palatoalveolar fricative than for the alveolar fricative due to tongue dorsum raising in languages and speakers where /ʃ/ exhibits a noticeable degree of palatality. This possibility is in accordance with vowel coarticulation data showing that the palatoalveolar fricative is somewhat more resistant than the alveolar fricative to vowel-dependent effects in tongue and jaw position [Recasens, 2012; Recasens and Espinosa, 2009]. On the other hand, the reason why regressive adaptation operates on /sʃ/ rather than on /ʃs/ may lie in differences in articulatory complexity between the two sequences: while the anticipation of /ʃ/ during preceding /s/ involves a single articulatory action, i.e., some tongue dorsum raising and a simultaneous increase in tongue contact behind the alveolar constriction, the anticipation of /s/ during preceding /ʃ/ requires the performance of two noncomplementary actions, i.e., tongue dorsum lowering, and tongue tip and blade raising for the formation of an alveolar constriction [Perkell et al., 1979]. These differences in articulatory complexity could also account for why /s/-to-/ʃ/ assimilation occurs less often at the progressive level in the cluster /ʃs/ than at the regressive level in the cluster /sʃ/ in many of the languages studied if we assume that the degree of segmental adaptation should be greater the easier it is for the two consonants to overlap in less versus more complex consonant sequences. Other articulation-based accounts appear to be less

Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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plausible, as for example that /ʃ/ triggers regressive rather than progressive assimilations since it exerts more anticipatory than carryover coarticulation on the adjacent phonetic segments; indeed, C-to-V effects for /ʃ/ in Catalan have been found to exert more anticipation than carryover on /a/ but the reverse on /i/ [Recasens et al., 1997]. Language-dependent differences in degree of assimilation have been attributed to factors which go beyond segmental phonetics [Niebuhr et al., 2011; Pouplier et al., 2011]. Thus, an explanation for why regressive place assimilations for /sʃ/ apply more frequently in English than in French has been sought in how often closed syllables and word-final fricatives occur in the language and also in whether the language is stress-timed or syllable-timed; on the other hand, a trend for French versus English to exhibit progressive assimilations in the case of the sequence /ʃs/ may be related to the fact that sequences of two palatoalveolar fricatives are less frequent and thus give rise to fewer perceptual confusions in the former language than in the latter. Another factor which may favor progressive place assimilation in the cluster /ʃs/ is the high frequency of occurrence of the palatoalveolar fricative in word-final position, as for example in European Portuguese dialects where /s/ becomes [ʃ] syllable-finally ([dojʃ ˈpes] dois pés ‘two feet’) and the sequence in question is realized typically as [(ʃ)ʃ] ([doj ˈʃakos] dois sacos ‘two sacks’, [doj(ʃ) ʃɐˈpatuʃ] dois sapatos ‘two shoes’; [Mateus and d’Andrade, 2000, p. 145; Leite de Vasconcelos, 1901, p. 120; Andrade, 2003]). This article will also explore how those mechanisms of intersegmental adaptation in the sequences /sʃ/ and /ʃs/ relate to cluster duration. It seems obvious that fricative clusters ought to be longer than single fricatives if involving two articulatory targets due to the time elapsed during the transition between the first and the second consonants. The relationship between the duration of assimilated clusters and single fricatives (as, for example, between the assimilated outcome of /sʃ/ and /ʃ/) is less straightforward. Literature studies show in this respect that, in comparison to single fricatives, fricative clusters which are realized through a single target may be longer [Holst and Nolan, 1995; Niebuhr et al., 2011; Niebuhr and Meunier, 2011; Nolan et al., 1996] or just as long [Pouplier et al., 2011]. These durational differences have been taken to reflect the two views on the nature of assimilatory processes referred to above: the former finding seems to support the traditional notion that assimilation is a cognitive process, i.e., speakers replace one consonant by another while keeping unmodified the sequential nature of the consonant cluster; the latter finding is more consistent with the assumption that assimilation results from extreme degrees of gestural overlap, i.e., the greater the degree of overlap, the more the cluster realization approaches the duration of a single fricative [Browman and Goldstein, 1990, 1992]. At least two other explanations may be proposed in order to account for the relationship between the duration of assimilated clusters and single fricatives [see Pouplier et al., 2011, for problems in inferring underlying production mechanisms from segmental duration]. A third possibility is that cluster duration proceeds largely independent of place assimilation: assimilated clusters could be longer than single fricatives presumably in slow and formal speech (i.e., /sʃ/ > [ʃʃ]), or else could shorten as much as single fricatives when speakers speak faster and less formally (i.e., /sʃ/ > [ʃʃ] > [ʃ]); to the extent that speakers may choose to emphasize the biconsonantal nature of the long consonant or not, this third possibility appears to be consistent with the notion that the realization of assimilated /sʃ/ is ruled by the cognitive component of speech. A fourth option is that the realization of /sʃ/ as [ʃ] has been generated through the elision of C1 = /s/ after severe articulatory reduction

of the apical or laminal gesture, i.e., /sʃ/ > [sʃ] > [ʃ], a process which ought to be most prone to apply when the consonant belongs to a frequent or function word [Bybee, 2001, 2006; Jun, 1995].

According to descriptive data from the literature [Bonet and Lloret, 1998; Recasens, 1996], Eastern Catalan and Western Catalan should differ in several respects regarding the phonetic realization of the clusters /sʃ/ and /ʃs/: (a) Eastern Catalan resembles English in that regressive assimilation applies obligatorily to /sʃ/ ([do(ʃ) ˈʃajs] dos xais ‘two muttons’), while /ʃs/ is supposed to exhibit blending into an intermediate realization between the two fricatives ([pe(sj) sjəˈlat] peix salat ‘salted fish’). As the parentheses in the phonetic transcriptions indicate, the assimilated outcome of /sʃ/ is expected to stay long or to shorten depending presumably on factors such as speech rate and speaker. Shortening applies to fricatives, rhotics and approximants though not to stops, nasals and laterals whether derived from a sequence of two identical phonemes (/ʃʃ/ [ʃʃ] > [ʃ], as in feix xinès ‘Chinese bundle’) or rendered long through place assimilation (/sʃ/ > [ʃʃ] > [ʃ], as for dos xais ‘two muttons’). Some support for this interpretation comes from EPG and acoustic data revealing that the cluster /sr/ (as in the sequence estàs rebentat ‘you are exhausted’), which may yield [r] through the derivation /sr/ > [rr] > [r] according to the shortening rule referred to above, may vary indeed in its realization from a long trill to a trill of comparable duration to underlying /r/ (as in ram ‘branch’) as prosodic prominence or the strength of the morphological boundary located between /s/ and /r/ decreases [Solé, 1999, 2002]. (b) Western Catalan differs crucially from Eastern Catalan in that /ʃs/ may undergo progressive assimilation ([pe(ʃ) ʃaˈlat] peix salat). A possible reason why speakers of this dialect favor this progressive assimilation process may be sought in a high degree of occurrence of the palatoalveolar fricative in word-final position resulting from the palatalization of /s/ after any (alveolo)palatal consonant in word-final clusters, as for example [aɲʃ] and [rejʃ] of /aɲs/ ‘years’ and /rejs/ ‘kings’. Unfortunately there are no available phonetic data for the cluster /sʃ/ in Western Catalan since word-initial /ʃ/ is realized as the affricate [tʃ] in this dialect. In the light of these descriptions and the general issues referred to in section 1.1, several topics regarding consonant adaptation in the Catalan sequences /sʃ/ and /ʃs/ will be investigated by means of EPG and acoustic analysis by varying the position of the cluster with respect to sentence stress. First, whether assimilation applies categorically or gradually for /sʃ/ in Eastern Catalan (regressive) and for /ʃs/ in Western Catalan (progressive). If operating categorically, these assimilatory phenomena would resemble analogous processes like the regressive place assimilation of a syllable-final alveolar nasal before an oral stop in Italian and Spanish, i.e., /np, nk/ > [mp, ŋk], which has been shown to apply almost without exception (see above). Second, whether the cluster /ʃs/ in Eastern Catalan is resolved through a more variable set of adaptation mechanisms than /sʃ/ such as blending or a two-target realization and, if so, the extent to which the production strategies in question depend on speaker and prosodic condition. Finally, whether cluster duration is related to the degree of articulatory adaptation between the two consecutive consonants and, therefore, assimilated clusters may parallel the duration of single fricatives to a larger extent than unassimilated clusters, and also whether /sʃ/ shortens after assimilation has taken place. 302

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1.2 The Catalan Case and Summary of Research Goals

Table 1. Sentence list with information about the prosodic and contextual conditions for the fricative sequences and single fricatives subjected to analysis

1.

Unstressed /sʃ/

2.

Stressed /sʃ/

3.

Unstressed /ʃs/

4.

Stressed /ʃs/

5.

Phrase-medial (unstressed) /s/

6.

Phrase-final (stressed) /s/

7.

Phrase-medial (unstressed) /ʃ/

8.

Phrase-final (stressed) /ʃ/

es prenia tres xarops ([ɛC#Ca/ə]) ‘he/she was taking three kinds of syrup’ li digué que matés xais ([eC#ˈCa]) ‘he asked him/her to kill some muttons’ per dinar, vull peix salat ([eC#Ca/ə]) ‘I want salted fish for lunch’ diu que aquest és un greix sa ([eC#ˈCa]) ‘he/she says that this animal fat is healthy’ és un canapé salat ([e#Ca/ə]) ‘this is a salty appetizer’ de llibretes en vull tres ([ˈɛC#]) ‘I want three notebooks’ el metge begué xarop ([e#Ca/ə]) ‘the doctor drank some syrup’ per dinar, jo no vull peix ([ˈeC#]) ‘I do not want any fish for lunch’

The target segments and segmental sequences have been underlined in the Catalan orthographic forms, and English glosses have been added.

2. Method 2.1 Sentence Material EPG and acoustic data were recorded for the sequences /sʃ/ and /ʃs/, and for /s/ and /ʃ/, embedded in the seven-syllable-long sentences listed in table 1. In these sentences, the two fricative clusters show up in the following conditions: in the less prominent sequences [e/ɛC#Ca] (Western) and [e/ɛC#Cə] (Eastern), where V1 bears lexical stress while V2 does not and sentence stress falls on the syllable following V2 (sentences 1 and 3 in table 1), and in the more prominent sequence [eC#ˈCa] (all dialects), where both V1 and V2 bear lexical stress and sentence stress falls on V2 (sentences 2 and 4). We refer to the former prosodic condition as ‘unstressed’ and to the latter as ‘stressed’ throughout the article. The single consonants /s/ and /ʃ/, on the other hand, occur in the same ‘unstressed’ sequence structure [e#Ca/ə] as above (sentences 5 and 7), and phrase-finally after the vowels /e/ or /ɛ/ bearing lexical and sentence stress (sentences 6 and 8). The former condition will be referred to as ‘phrase-medial’ and the latter as ‘phrase-final’ throughout the article. The rationale for including the phrase-medial and phrase-final realizations of /s/ and /ʃ/ in our data set was twofold. A first reason was to elicit a large frication noise frequency range for single fricatives (in comparison to syllable-initial fricatives, their syllable-final cognates usually exhibit a lower spectral peak). A second reason was to make sure that data for /ʃ/ would be available for Western Catalan. Indeed, as stated in the ‘Introduction’ section, data for /ʃ/ could be only obtained sentence-finally for speakers of this dialect (also for the Eastern Catalan speaker MO) since they all realize word-initial /ʃ/ as the affricate [tʃ] in the sequences /s#ʃ/ and /V#ʃ/ (see conditions 1, 2 and 7 of table 1).

The EPG data for the sentence material listed in table 1 were recorded 10 times by the Eastern Catalan subjects DR (the first author), JP and JC, who are proficient Catalan speakers. Linguopalatal contact configurations were gathered every 10 ms with artificial palates equipped with 62 electrodes Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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2.2 Speakers and Recording Procedure

Rows of electrodes 1 2

Alveolar zone

3 4 5 6

Palatal zone

7 8 1

2

3

4

5

6

7

8

Columns of electrodes

Fig. 1. Projection of the artificial palate showing the location of the rows and columns of electrodes over the alveolar and palatal zones. Electrodes are filled if they have been contacted by the tongue and unfilled if they have not.

simultaneously with acoustic data by means of the WinEPG system of Articulate Instruments [Hardcastle et al., 1989]. Figure 1 shows the placement of the eight rows and columns of electrodes, and of the alveolar and palatal zones, on the surface of the artificial palate. Segmentation was carried out on spectrographic displays using the Computerized Speech Lab analysis system of Kay Elemetrics after downsampling the acoustic signal from 22,050 to 11,025 Hz, and converting the EPG data into Computerized Speech Lab format for simultaneous visual inspection of the waveform, spectrograms and linguopalatal contact patterns. The acoustic data for the EPG tokens were not subjected to analysis due to possible interferences between the artificial palate and the frication noise, and also because, as pointed out next, acoustic data for the same fricative clusters and single fricatives were recorded by another set of Eastern Catalan speakers. An additional set of 9 speakers made acoustic recordings of the sentences presented in table 1 with no artificial palate: 4 male Eastern Catalan speakers (DR, the first author; AL, MO, SO); 5 female Western Catalan speakers (MA, EV, IM, CL, NO). Speakers were between 20 and 40 years of age for the most part, speak Catalan in their everyday life, and were judged to be fairly representative of their native dialect. Sentences were recorded 7 times by all 9 speakers with Computerized Speech Lab at the Phonetics Laboratory of the Institut d’Estudis Catalans in Barcelona.

Both for the consonant sequences and for the single fricatives, the onset and offset of the frication noise were identified on spectrographic displays. Frication onset was labeled at the beginning of a patch of high-intensity noise occurring immediately after the offset of formant structure for the preceding vowel. For most speakers, the offset of the fricative segment was harder to establish since the intense and high-frequency frication phase was often followed by a shorter weak and lowfrequency frication period before the onset of voicing for the following vowel. According to the EPG linguopalatal contact patterns, this second frication phase occurs as the constriction narrowing widens while there is still some airflow going through the glottis. Since including the period in question as part of the fricative would have caused the noise frequency values measured at the first frication phase to lower substantially, we decided to identify two consonant offset points for different purposes: the offset of the intense and high-frequency noise for conducting the spectral analysis, i.e., frequency data were obtained for this noise portion only, and the offset of the overall frication noise at about voicing onset for the following vowel for duration measurements, i.e., fricative consonants and clusters were taken to last from onset to offset of the overall frication noise [see Behrens and Blumstein, 1988; Jongman et al., 2000, and Soli, 1981 regarding this same procedure for measuring fricative consonant duration].

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2.3 Segmentation

2.4 Data Analysis

2.4.2 Acoustic Data A frequency measure of the frication noise, i.e., COG, was computed for all tokens of /s/, /ʃ/, /sʃ/ and /ʃs/ using a MatLab script written by Leonardo Lancia. COG was calculated by multiplying each frequency in Hertz by the amplitude in decibel at that frequency, summing the products across all frequencies in the relevant range, and dividing the outcoming value by the sum of all the amplitude values. COG measures should be inversely dependent on the dimensions of the cavity in front of the lingual constriction [Cho et al., 2002]. They were obtained from FFT spectra over a frequency range spanning from 1 to 11 kHz using a 25-ms length Hamming window which was shifted through the single fricative or the fricative sequence in steps of 10 ms. Hence the number of spectral slices varied according to the overall duration of the frication noise. The lower frequency limit of the COG range is intended to avoid artifacts due to possible residues of voicing. COG values analogous to those taken for the EPG similarity index were calculated: mean COG averaged across the total number of individual slices during the frication noise, which provides information about the Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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2.4.1 EPG Data The linguopalatal contact data for /sʃ/ and /ʃs/ were analyzed applying the EPG similarity index method developed by Guzik and Harrington [2007] and Pouplier et al. [2011]. This index computation procedure involves several steps. First, a cross-token average contact per electrode was calculated at the fricative midpoint for each palatogram of phrase-medial /s/ and /ʃ/. A /s/-/ʃ/ difference pattern was then created by subtracting for each electrode the value of the /ʃ/ palatogram from that of the /s/ palatogram; this subtraction procedure yielded positive or negative electrode values in the /s/-/ʃ/ difference pattern depending on whether the contact value for /s/ was higher or lower than that for /ʃ/, respectively. The entire /s/-/ʃ/ difference pattern was normalized by dividing each electrode’s value in this pattern by the sum of the absolute values of the pattern as a whole. Finally, for each palatogram of the target sequences /sʃ/ and /ʃs/, the values for all electrodes in the difference pattern which were activated in the target pattern were summed up with their own sign, and the values for all electrodes in the difference pattern which were not activated in the target pattern were summed up with their own opposite sign. The addition of the two summation results yielded an index value between –1 and 1, with –1 being maximally /ʃ/-like and 1 being maximally /s/-like. Several criteria were applied in order to determine whether a given fricative cluster was implemented through assimilation, blending or two articulatory targets. First, the two following measures were calculated for the fricative sequences and for the single fricatives: the mean EPG similarity index value across all the EPG contact patterns, which provides an overall measure of place of articulation; the EPG similarity index range by subtracting the maximal and minimal index values throughout the entire sequence, which provides a measure of the amount of linguopalatal contact change over time. Assimilation was taken to occur when the mean EPG similarity index value for a given cluster did not differ significantly from those for /s/ or /ʃ/, and its index range was comparable to those for the single consonants; on the other hand, blending or a two-consonant target was considered to take place when the mean EPG similarity index value for the cluster differed significantly from those for /s/ or /ʃ/, and its index range was larger than those for the single consonants. Moreover, since mean index values correspond to averages across temporal slices, the temporal evolution of the EPG similarity index was also subjected to analysis before drawing definite conclusions about whether assimilation applied or not. For this purpose, the index values for /sʃ/ and /ʃs/ were compared to those for the single consonants at 25, 50 and 75% of the frication noise by dividing the distance between /s/ and /ʃ/ into three equidistant bands corresponding to /s/, /ʃ/ and an intermediate domain: whenever the mean value for /sʃ/ or /ʃs/ fell within the /s/ band or within the /ʃ/ band throughout the entire sequence, it was assigned respectively to /s/ or to /ʃ/, thus meaning that /ʃ/ was assimilated to /s/ in the former case and that /s/ was assimilated to /ʃ/ in the latter; whenever the mean value for /sʃ/ or /ʃs/ fell within the intermediate band, blending or a two-consonant target mechanism was taken to occur depending on whether the value in question held stable or changed from one target to the next. Moreover, an analysis of the index trajectories over time allowed it to be determined with more precision whether the unassimilated sequence productions exhibited a stable blended realization, or else involved a change in articulatory target during the cluster and at which temporal point this change occurred.

overall spectral noise frequency characteristics; COG range between the highest and lowest COG frequency values through all the temporal slices, which provides a measure of COG variability over time (the higher the COG range, the more variable it is); COG trajectories over time which allow finding out how much and where spectral change occurs during the frication noise. The analysis criteria for determining whether a given cluster underwent assimilation or blending or was implemented through two articulatory targets were identical to those used for the evaluation of the EPG index data (see section 2.4.1). 2.4.3 Statistics In order to determine statistically whether sibilant assimilation occurred or not in the clusters under analysis, a Generalized Linear Model analysis was performed on the speakers’ cross-token EPG index, COG and duration values with ‘consonant’ as fixed variable (and the variable levels ‘phrasemedial /s/’, ‘phrase-medial /ʃ/’, ‘unstressed /sʃ/’, ‘stressed /sʃ/’, ‘unstressed /ʃs/’ and ‘stressed /ʃs/’) and ‘speaker’ as random variable. Separate tests were performed for each dialect using the IBM SPSS Statistics 20 package. Data for phrase-final /s/ and /ʃ/ were not evaluated statistically in Eastern Catalan since they cannot be strictly compared with those for the fricative clusters in view of the fact that fricative clusters do not occur prepausally after sentence stress; as for Western Catalan, however, the COG values for /ʃ/ correspond to the phrase-final realizations of the palatoalveolar fricative since palatoalveolar fricative realizations of /ʃ/ do not occur word-initially in this dialect (see section 2.1). In all statistical tests, the significance level was established at p < 0.05, and Bonferroni’s post hoc comparisons were carried out whenever appropriate.

3. Results: EPG Data

The statistical analysis run on the EPG similarity index values yielded a main consonant effect [F(5, 12) = 23.06, p < 0.001]. Statistical results will be described mostly with reference to figure 2, which presents the index values for /s/, /ʃ/, /sʃ/ and /ʃs/ across speakers (top graph) and for the 3 individual speakers (bottom graphs). Let us deal first with the articulatory differences between /s/ and /ʃ/. Figure 2 reveals the presence of very different index values between the two fricatives across speakers and for each individual speaker, i.e., about 0.6 for /s/ and about –0.6/–0.8 for /ʃ/ (this difference was statistically significant at the p < 0.001 level). Linguopalatal contact differences between the two consonants become apparent in the EPG patterns for phrase-medial /s/ and /ʃ/ displayed in figure 3. All speakers make a clear articulatory distinction between the two fricatives: the lingual constriction is more anterior for /s/ (at about row 2 for DR and JC, and at rows 3–4 for JP) than for /ʃ/ (at rows 3–5 for DR, 4–5 for JP and 3–4 for JC), and dorsopalatal contact size behind constriction location is larger for /ʃ/ than for /s/ for all speakers. Figures 4 and 5 allow us to study the temporal evolution of the EPG similarity index values for /s/ and /ʃ/. The former figure displays the frequency of occurrence of the index values at 25, 50 and 75% of the frication noise across speakers, and the latter the EPG index trajectories over time during the frication noise both across speakers and for the individual subjects. According to the left graphs of figure 4, phrase-medial /s/ (unfilled bars) and /ʃ/ (filled bars) occupy extreme positions, i.e., close to –1 the latter and to 1 the former at 25, 50 and 75% of the frication noise, though less so at 25% where the COG values for /s/ are lower than expected since the lingual constriction is not well-formed at consonant onset and therefore there is less central alveolar contact 306

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3.1 EPG Similarity Index

Across speakers

Index value

1.0 0.6 0.2 –0.2 –0.6 –1.0

med fin med fin unstr str unstr str ʃ sʃ ʃs s

Speaker JP

Speaker DR

Speaker JC

Index value

1.0 0.6 0.2 –0.2 –0.6 –1.0 med fin med fin unstr str unstr str s

ʃ

sʃ

ʃs

med fin med fin unstr str unstr str s

ʃ

sʃ

ʃs

med fin med fin unstr str unstr str s

ʃ

sʃ

ʃs

Fig. 2. Mean EPG similarity index values and ranges for phrase-medial and phrase-final /s/ and /ʃ/, and for unstressed and stressed /sʃ/ and /ʃs/, in Eastern Catalan across speakers (top) and for all individual speakers (bottom).

s

ʃ

Speaker DR

Speaker JP

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Speaker JC

Fig. 3. Cross-token linguopalatal contact patterns for phrasemedial /s/ and /ʃ/ taken at the midpoint of the frication period according to speakers DR, JP and JC. Electrodes have been filled in black or gray, or have been left unfilled, depending on contact activation (above 80%, between 40 and 80% and below 40%, respectively).

%

100

s ʃ

25% timepoint

80

sʃ ʃs

60 40 20 0 100

50% timepoint

80 60 40 20 0 100

75% timepoint

80 60 40 20

EPG index value

.1 0. 1 0. 3 0. 5 0. 7 0. 9

.3

–0

.5

–0

.7

–0

.9

–0

–0

.5 –0 .3 –0 .1 0. 1 0. 3 0. 5 0. 7 0. 9

.7

–0

–0

–0

.9

0

EPG index value

Fig. 4. Frequency of occurrence of the EPG similarity index values for phrase-medial fricative sequences (right) and for single fricatives (left) at 25, 50 and 75% of the frication noise across speakers. Data for /sʃ/ and /ʃs/ correspond to the unstressed and stressed conditions combined, and those for /s/ and /ʃ/ to the phrase-medial position.

3.1.1 Cluster /sʃ/ The EPG similarity index values for /sʃ/ (whether unstressed or stressed) turned out to differ significantly from those for phrase-medial /s/ (p < 0.001) but not from those for phrase-medial /ʃ/. Indeed, the graphs in figure 2 show that the index values 308

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at this temporal point than later on during the consonant. Data for /s/ (continuous lines) and /ʃ/ (dashed lines) in the left graphs of figure 5, on the other hand, reveal that, while the trajectories for /ʃ/ remain quite steady during the first two thirds of the frication noise, those for /s/ show some upward movement at consonant onset resulting from some gradual narrowing at the lingual constriction location.

Index value

ʃs (unstr) ʃs (str)

sʃ (unstr) sʃ (str)

ʃ

s 1.0

Across speakers

0.6 0.2 –0.2 –0.6 –1.0 0

52.5

102.5

152.5

0

52.5

102.5

152.5

1.0

Speaker DR

0.6 0.2 –0.2 –0.6 –1.0 1.0

Speaker JP

0.6 0.2 –0.2 –0.6 –1.0 1.0

Speaker JC

0.6 0.2 –0.2 –0.6 –1.0 0

52.5

102.5 Time (ms)

152.5

0

52.5

102.5

152.5

Time (ms)

Fig. 5. EPG similarity index trajectories over time for phrase-medial /s/ and /ʃ/ (left) and for unstressed

Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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and stressed /sʃ/ and /ʃs/ (right) across speakers and for all individual speakers. The index trajectories have been lined up at the onset of the fricative cluster or single fricative consonant, and cross-token averaging has been carried out frame by frame as long as there were three tokens available.

ʃ

sʃ stressed

Speaker JC

Speaker JP

Speaker DR

unstressed

for this cluster lie very close to those for /ʃ/, and that this is more so for some speakers (JP, JC) than for others (DR). The EPG contact patterns at fricative midpoint for /sʃ/ and /ʃ/ displayed in figure 6 are very much in agreement with the index values plotted in figure 2. Thus, contact patterns for unstressed and stressed /sʃ/ for speaker JP and for stressed /sʃ/ for speaker JC are practically identical to or show more dorsopalatal contact than those for /ʃ/; on the other hand, in comparison to the contact configurations for /ʃ/, those for stressed /sʃ/ for speaker DR and for unstressed /sʃ/ for speaker JC may exhibit less central contact and/or some more alveolar contact fronting and thus, a slightly more /s/-like articulation. Figure 2 (top graph) also reveals the presence of similar EPG index ranges for unstressed and stressed /sʃ/ (0.39, 0.31) and for phrase-medial and phrase-final /ʃ/ (0.39, 0.35), which suggests that small changes in EPG contact configuration occur during this cluster. The similarity between the temporal evolution of the EPG index values for /sʃ/ and /ʃ/ is confirmed through inspection of figures 4 and 5. According to the three right graphs of figure 4, values for unstressed and stressed /sʃ/ combined (hatched bars) are always below 0 and remain highly stable across the three temporal periods; a comparison between the location of these index values and those for the single fricatives 310

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Fig. 6. Cross-token linguopalatal contact patterns for phrase-medial /ʃ/ and for unstressed and stressed /sʃ/ at the frication midpoint for all individual speakers. See captions of figures 1 and 3 for details.

displayed in the left graphs reveals that the values for /sʃ/ clearly overlap with those for /ʃ/ while extending towards the values for /s/ to some extent. The three right graphs in figure 5, on the other hand, show that the trajectories for unstressed and stressed /sʃ/ (right graphs, continuous lines) overlap almost perfectly with or run very close to those for /ʃ/ (left graphs, dashed lines) and remain quite stable during the entire cluster. Based on these data, it may be suggested that /sʃ/ undergoes regressive place assimilation in Eastern Catalan whether assimilation is complete or partial (see section 1.1). 3.1.2 Cluster /ʃs/ Statistical results for the EPG similarity index values indicate that unstressed and stressed /ʃs/ do not differ significantly between each other, that unstressed /ʃs/ differs from /ʃ/ (p < 0.01) and from unstressed and stressed /sʃ/ (p < 0.05, p < 0.01) but not from /s/, while stressed /ʃs/ differs from /s/ (p < 0.001) but not from either /ʃ/ or /sʃ/. In agreement with these statistical results, figure 2 shows that the values for /ʃs/ tend to occupy the /s/ domain or the /ʃ/ domain depending on whether the cluster is unstressed or stressed, respectively; moreover, speakers differ among themselves in exhibiting a more /s/-like (DR, JP) or a more /ʃ/-like (JC) realization of the cluster. An important point needs to be made, namely, that in addition to being split according to stress condition, the index values for /ʃs/ generally lie somewhere between those for /s/ and /ʃ/. Figure 2 also reveals that the EPG similarity index ranges for /ʃs/ (0.75, 0.79) are fairly large and definitely greater than those for /ʃ/ and /sʃ/ (0.30–0.40) thus meaning that, as shown below, the production of this cluster may involve considerable linguopalatal contact changes over time. According to the right graphs of figure 4, the index values for unstressed and stressed /ʃs/ combined (right graphs, dotted bars) tend to cluster around an intermediate position between those for /s/ and those for /ʃ/ plotted in the left graphs, exhibit much dispersion and no clear frequency peak, and increase gradually from the 25% to the 75% temporal points. As shown by figure 5, the index trajectories for /ʃs/ (right graphs, dotted lines) rise from the /ʃ/ to the /s/ targets in the case of both speakers DR and JP (unstressed and stressed condition) and of speaker JC (unstressed condition only). Linguopalatal contact patterns for unstressed /ʃs/ and for stressed /ʃs/ (all speakers) presented in figure 7 reveal indeed a decrease in dorsopalatal contact and/or an increase in lingual constriction fronting and thus, a change from a more /ʃ/-like to a more /s/-like configuration, as we proceed from the 25% timepoint to the midpoint of the frication period. In sum, /ʃs/ appears to be implemented not through assimilation but mostly through a two-target realization and, less so, through a stable intermediate realization between the two fricatives.

Figure 8 reports duration data for the fricative sequences and the single fricatives in order to investigate whether there is a dependency relationship between segmental duration and the adaptation mechanisms operating in fricative clusters. As pointed out in section 2.4.3 and shown by the bars in figure 8, the durations for phrase-final /s/ and /ʃ/ cannot be compared statistically with those for /sʃ/ and /ʃs/ since they are especially long by virtue of occurring prepausally. Statistical results for the remaining segmental material yielded a main consonant effect [F(5, 10) = 8.34, p = 0.002], which turned out to be associated with a significantly longer duration for stressed /ʃs/ than for unstressed Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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3.2 Duration

Unstressed ʃs

Stressed ʃs

50% timepoint

25% timepoint

50% timepoint

Speaker JC

Speaker JP

Speaker DR

25% timepoint

Fig. 7. Cross-token linguopalatal contact patterns for unstressed and stressed /ʃs/ at the 25 and 50% timepoints during the frication noise for all individual speakers. See captions of figures 1 and 3 for details.

Across speakers ms

300 250 200 150 100 50 0 med fin med fin unstr str unst str

s

ʃ

sʃ

ʃs

Speaker JP

Speaker DR

Speaker JC

ms 350 300 250 200 150 100 50 0 s

ʃ

sʃ

ʃs

med fin med fin unstr str unst str

s

ʃ

sʃ

ʃs

med fin med fin unstr str unst str

s

ʃ

sʃ

ʃs

Fig. 8. Segmental durations for phrase-medial and phrase-final /s/ and /ʃ/ and for unstressed and stressed /sʃ/ and /ʃs/ across speakers (top) and for all individual speakers (bottom). Error bars correspond to one standard deviation of the mean.

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med fin med fin unstr str unst str

/sʃ/ and (unstressed) /s, ʃ/ (p < 0.05, p < 0.01, p < 0.05), and for stressed /sʃ/ than for (unstressed) /ʃ/ (p < 0.05). Unstressed /sʃ/ and /ʃs/ did not differ between each other and from (unstressed) /s, ʃ/. These results suggest that duration differences between fricative sequences and single fricatives are due to stress rather than to the cluster production strategy. Thus, clusters were longer than single consonants if stressed but not if involving different degrees of mutual adaptation and equal degrees of stress, as for unstressed /sʃ/ which undergoes regressive assimilation and unstressed /ʃs/ which does not. In any case, as revealed by figure 8 and in line with the duration data for the acoustic material presented in section 4.2, the fact that unstressed /sʃ/ was (nonsignificantly) shorter than unstressed /ʃs/ for all speakers (see bottom graphs) could be taken in support of the notion that clusters may become shorter when they undergo assimilation than when they do not. Moreover, as argued in section 1.1, a short realization of unstressed /sʃ/ for all speakers could correspond to an abridged version of the assimilated outcome [ʃʃ] if we assume that the long outcome in question may occur at least in slow speech. The close similarity between the articulatory configurations for /sʃ/ and /ʃ/ for all speakers’ data referred to in sections 3.1.1 and 1.2 appears to disconfirm the possibility that /sʃ/ shortens to [ʃ] through large degrees of gestural overlap.

4. Results: Acoustic Data

4.1.1 Eastern Catalan Mean COG acoustic differences among fricative sequences and single fricatives for the Eastern Catalan speakers (fig. 9, top) parallel those for the EPG index values in many respects. The statistical test run on the COG data yielded a main consonant effect [F(5, 13) = 23.00, p < 0.001] which, in addition to significant differences between /s/ and /ʃ/ (p < 0.001), turned out to be associated with two major findings. First, unstressed and stressed /sʃ/ were found to differ significantly from /s/ (p < 0.001) but not from /ʃ/, which is in agreement with results for the EPG data (see section 3.1.1), suggesting that the cluster /sʃ/ undergoes regressive assimilation. The top graph of figure 9 shows indeed that the COG values for /sʃ/ lie very close to those for /ʃ/. In the second place, unstressed and stressed /ʃs/ differed significantly from phrase-medial /ʃ/ (p < 0.001, p < 0.01) and from /sʃ/ whether unstressed (p < 0.001, p < 0.05) or stressed (p < 0.05), but not from phrase-medial /s/. As shown in the graph, this finding results from the COG for /ʃs/ being closer to that for /s/ than to that for /ʃ/ though, as shown by the temporal characteristics described below and the EPG data in section 3, it should not be taken to imply that /ʃs/ undergoes regressive assimilation in Eastern Catalan. The top graph in figure 9 also reveals the presence of a lower COG value for /s/ in phrase-final versus phrase-medial position (see also the Western Catalan data displayed in fig. 11), which is consistent with syllable-final consonant allophones often involving less dorsopalatal contact and more constriction retraction and jaw opening than syllable-initial ones [Fougeron, 1999; Ohala and Kawasaki, 1984]. It should be noticed, however, that the EPG data for a different set of speakers reported in section 3.1 does not support this point regarding the tongue articulator since no linguopalatal contact differences were observed between phrase-final /s/ and phrase-medial /s/. As exemplified by the data Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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4.1 Center of Gravity

Cross-speaker means COG 5,500 (Hz) 4,500 3,500 2,500 med fin med fin unstr str unst str s sʃ ʃs ʃ

Speaker DR

Speaker AL

Speaker SO

COG 5,500 (Hz) 4,500 3,500 2,500 med fin med fin unstr str unst str s sʃ ʃs ʃ

med fin med fin unstr str unst str s sʃ ʃs ʃ

med fin med fin unstr str unst str s sʃ ʃs ʃ

for 3 speakers in the bottom graphs of figure 9, essentially all Eastern Catalan subjects exhibit the same COG relationship among /s/, /ʃ/, /sʃ/ and /ʃs/. In order to gain some more knowledge about the speakers’ production strategies for the clusters /sʃ/ and /ʃs/ in Eastern Catalan, an analysis of the COG temporal variability needs to be carried out. The cross-speaker COG ranges in figure 9 show that, in comparison to the ranges for phrase-medial /s/ and /ʃ/ (about 550 Hz), those for / sʃ/ show a similar size (about 450–500 Hz) while those for /ʃs/ are clearly greater (about 600–750 Hz). A higher degree of COG temporal variability for /ʃs/ than for /sʃ/ is also consistent with the COG temporal trajectories displayed in figure 10. A comparison between the cross-speaker and individual speakers’ trajectories for the two clusters in the right graphs with those for the single fricatives in the left graphs shows the following trends: the trajectories for unstressed and stressed /sʃ/ run close to the trajectory for /ʃ/ and stay stable from cluster onset to offset; the trajectories for /ʃs/ are intermediate between those for /s/ and /ʃ/, with those for the unstressed condition lying closer to those for /s/ than the ones for the stressed condition and the former exhibiting no noticeable COG changes and the latter a change from a /ʃ/-like COG target to an /s/-like COG target. These COG trajectories are consistent with an assimilatory account for /sʃ/, and with a blending or a two-target account for /ʃs/ depending on stress. A comparison between the EPG contact index trajectories for /ʃs/ in figure 5 and the corresponding COG spectral trajectories in figure 10 reveals that they are similar in several respects but not in others. They differ in that the trajectories for unstressed /ʃs/ are more stable and closer to /s/ in the case of the COG than the EPG data, and agree in that the trajectories for stressed /ʃs/ show two targets and run closer to /ʃ/ than those 314

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Fig. 9. Mean COG values and ranges for phrase-medial and phrase-final /s/ and /ʃ/, and for unstressed and stressed /sʃ/ and /ʃs/, in Eastern Catalan across speakers (top) and for 3 individual speakers (bottom). Data for speaker MO have not been displayed for reasons pointed out in section 2.1.

Across speakers

COG (Hz) 5,500

ʃ

s

ʃs (unstr) ʃs (str)

sʃ (unstr) sʃ (str)

4,500

3,500

2,500 0

52.5

0

52.5

102.5

152.5 0

102.5

52.5

152.5

Speaker DR

5,500

4,500

3,500

2,500

Speaker AL

5,500

4,500

3,500

2,500

Speaker SO

5,500

4,500

3,500

2,500 102.5 Time (ms)

152.5

0

52.5

102.5

152.5

Time (ms)

Fig. 10. COG temporal trajectories for phrase-medial /s/ and /ʃ/, and for unstressed and stressed /sʃ/

Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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and /ʃs/, in Eastern Catalan across speakers and for 3 individual speakers. See figure 5 caption for details. Data for speaker MO have not been displayed for reasons pointed out in section 2.1.

for unstressed /ʃs/. It is hard to see why the articulatory and acoustic signals show some noticeable differences for the cluster /ʃs/. Possible factors involved may be sought in the fact that the two data samples were recorded by different speakers and that the acoustic signal reflects changes in articulatory structures other than the tongue (such as the jaw), but also in the methodological criteria that were used for measuring and representing the two signal indices and in nonlinearities that may arise between the articulation and the acoustic output. 4.1.2 Western Catalan The COG data for the Western Catalan speakers (fig. 11) yielded a significant consonant effect [F(3, 12) = 18.51, p < 0.001] which according to post hoc tests is associated with significant differences between /s/ and /ʃ/ (p < 0.001) and between /ʃs/ and /s/ (p < 0.01). Differences between /ʃs/ and /ʃ/ are only barely significant for unstressed /ʃs/ (p < 0.05) but not for stressed /ʃs/. Consistently with these statistical results, the top graph of figure 11 shows that the COG values for /ʃs/ are intermediate between those for /s/ and /ʃ/ and, in contrast with the COG values for /ʃs/ in Eastern Catalan, lie closer to the palatoalveolar fricative than to the alveolar fricative. A look at the data for the individual speakers plotted in the bottom graphs reveals that the Western Catalan subjects do not cluster together regarding the phonetic realization of /ʃs/: in agreement with the descriptive data for this dialect (see ‘Introduction’), speakers like MA and NO exhibit a low COG value for /ʃs/ equalling or approaching very closely the COG value for /ʃ/; speakers like EV and IM, on the other hand, behave like the Eastern Catalan subjects in showing COG values for /ʃs/ which lie between those for /s/ and /ʃ/. Regarding temporal variability, COG ranges for /ʃs/ in Western Catalan are larger if stressed (785 Hz) than if unstressed (531 Hz, fig. 11). Accordingly, data across speakers and for the individual speakers displayed in figure 12 indicate that the COG trajectories in question remain quite stable except for speaker IM, who exhibits a COG rising trajectory from a /ʃ/-like to an /s/-like target in the case of the stressed cluster condition (speaker CL whose data are not displayed in the figure behaves similarly to speaker IM in this respect). Therefore, Western Catalan /ʃs/ may undergo progressive assimilation, blending or a two-target sequence depending on speaker and prosodic condition.

Fricative cluster durations may be compared with the durations of single fricatives in phrase-medial but not in phrase-final position where, as shown for the Eastern Catalan dialect in figure 13, /s/ and /ʃ/ are especially long due to final lengthening (see also sections 2.4.3 and 3.2). Data for Western Catalan are not displayed since this dialect lacks a fricative realization of word-initial /ʃ/. The Eastern Catalan duration data yielded a main consonant effect [F(5, 12) = 16.48, p < 0.001] which, as revealed by the bars plotted in figure 13, is related to significantly longer durations for unstressed and stressed /ʃs/ than for (unstressed) /s/ and /ʃ/ (mostly at the p < 0.001 level of significance), for stressed /ʃs/ than for unstressed /sʃ/ (p < 0.01), and for stressed /sʃ/ than for (unstressed) /ʃ/ (p < 0.05). There are no significant differences between unstressed /ʃs/ and unstressed /sʃ/, and between unstressed /sʃ/ 316

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4.2 Durations

Across speakers COG (Hz)

7,000 6,000 5,000 4,000 3,000 2,000 med

fin

fin

unstr

str ʃs

ʃ

s

Speaker MA

Speaker NO

Speaker EV

Speaker IM

COG 7,000 (Hz) 6,000 5,000 4,000 3,000 2,000

7,000 6,000 5,000 4,000 3,000 2,000 med

fin s

fin

unstr

ʃ

str ʃs

med

fin s

fin ʃ

unstr

str ʃs

and any of the two (unstressed) consonants /s/ and /ʃ/. If we discard the effect of stress, these data suggest that there is an inverse relationship between duration and adaptation degree for the fricative clusters under analysis given that unstressed /sʃ/ (where C1 assimilates to C2) has the same duration as (unstressed) /ʃ/, while unstressed /ʃs/ (which exhibits no assimilation) is longer than both (unstressed) /s/ and /ʃ/. Moreover, as argued for the articulatory data in section 3.2, the fact that unstressed /sʃ/ does not differ from unstressed /ʃ/ is consistent with the outcome [ʃ] of /sʃ/ being generated from assimilated [ʃʃ] through a shortening process. Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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Fig. 11. Mean COG values and ranges for phrase-medial and phrase-final /s/, phrase-final /ʃ/, and unstressed and stressed /ʃs/, in Western Catalan across speakers (top) and for 4 individual speakers (bottom).

Across speakers COG (Hz)

7,000 s ʃ ʃs (unstr)

6,000

ʃs (str)

5,000 4,000 3,000 0

52.5

102.5

152.5

Speaker MA

Speaker NO

Speaker EV

Speaker IM

COG 7,000 (Hz) 6,000 5,000 4,000 3,000

7,000 6,000 5,000 4,000 3,000 52.5

0

102.5

152.5

0

52.5

102.5

152.5

Time (ms)

Time (ms)

Fig. 12. Mean COG temporal trajectories for phrase-medial /s/ and phrase-final /ʃ/, and for unstressed

and stressed /ʃs/, in Western Catalan across speakers and for 4 individual speakers. See figure 5 caption for details.

The present study throws new light on the production mechanisms for the fricative sequences /sʃ/ and /ʃs/ using data for Catalan dialects. Articulatory data and COG spectral measures show that /sʃ/ undergoes regressive assimilation in Eastern Catalan and therefore that /s/ takes the realization of the following palatoalveolar fricative all throughout its duration for all speakers subjected to analysis. It seems that this consonant assimilation process applies categorically and, therefore, independently of speaker and stress condition (and presumably of speech rate). This possibility is 318

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5. Discussion

ms 300 250 200 150

50 0

med s

fin

med

fin

unstr

ʃ

sʃ

str

unstr str ʃs

Fig. 13. Segmental durations for phrase-medial and phrasefinal /s/ and /ʃ/ and for unstressed and stressed /sʃ/ and /ʃs/ across speakers of Eastern Catalan. Error bars correspond to one standard deviation of the mean.

consistent with /sʃ/ and /ʃ/ exhibiting essentially the same linguopalatal contact configurations and COG spectral values. This finding parallels the categorical outcome of place assimilations in Italian and Spanish /nC/ clusters [Farnetani and Busà, 1994; Honoroff, 1999]. The presence of a trace of the /s/ alveolar gesture cannot be discarded in the case of speaker DR. On the other hand, the cluster /ʃs/ exhibits a highly variable realization in Eastern Catalan, while Western Catalan speakers may also show progressive assimilation. Whenever there is no assimilation, the sequence in question is implemented through a blended and temporally stable phonetic outcome which is intermediate between /s/ and /ʃ/, or else a two-target realization; moreover, /ʃs/ may approach /s/ or /ʃ/ depending on speaker and prosodic condition, i.e., unstressed /ʃs/ lies closer to /s/ and stressed /ʃs/ closer to /ʃ/ in Eastern Catalan. The high frequency of two-target realization cases for the sequence /ʃs/ was a relatively unexpected outcome and could be due to the fact that the sentences subjected to recording and analysis were relatively short and uttered in read speech. It is hypothesized that the two fricatives of this consonantal sequence should blend more often in faster and less accurate speech. In sum, judging from the degree of similarity with respect to /s/ and /ʃ/ and the degree of spatiotemporal variability as a function of speaker and stress condition, the cluster /sʃ/ appears to be implemented through a cognitive assimilation rule and /ʃs/ through several low-level phonetic mechanisms. The article also looked into the relationship between cluster duration and the mechanisms of intersegmental adaptation operating in the case of /sʃ/ and /ʃs/ in Eastern Catalan. A comparison between the duration data for the two sequences reveals that cluster duration is related to assimilation degree insofar as (unassimilated) /ʃs/ tends to be longer than the two simple consonants and (assimilated) /sʃ/. The finding that assimilated realizations of /sʃ/ have roughly the same duration as single /ʃ/ is not likely to result from a low-level phonetic process involving extreme degrees of gestural overlap since /sʃ/ did not yield a blended outcome but the replacement of C1 by C2 both according to the articulatory and the COG spectral data. Among the other possible options, namely, regressive assimilation followed by shortening of the long phonetic outcome, i.e., /sʃ/ > [ʃʃ] > [ʃ], and C1 elision following extreme gestural reduction, i.e., /sʃ/ > [sʃ] > [ʃ], the former appears to be more consistent with previous experimental data and phonological descriptions on Catalan consonant sequences yielding a long consonant realization. In any case, the relationship between segmental Fricative Clusters /sʃ/ and /ʃs/ in Catalan

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duration and articulatory accommodation for the cluster /sʃ/ needs to be explored in future studies by taking into account different lexical, prosodic and speech rate and style conditions. Based on evidence reported in the present article and in previous studies dealing with English and French (see ‘Introduction’), we propose next a preliminary production-based model accounting for the degree and direction of the segmental adaptation mechanisms operating in the fricative clusters /sʃ/ and /ʃs/. The model predicts that the palatoalveolar fricative /ʃ/ ought to prevail over the alveolar cognate /s/ in both clusters /sʃ/ and /ʃs/ and more so in the former than in the latter, which is in line with regressive assimilation in the cluster /sʃ/ operating more often than progressive assimilation in the sequence /ʃs/. Prevalence of /ʃ/ over /s/ has been attributed to tongue dorsum raising imposing stricter production requirements on /ʃ/ than on /s/, and may also be associated with differences in articulatory complexity between the two clusters /sʃ/ and /ʃs/: the fact that C2 anticipation involves a single articulatory action in the sequence /sʃ/ and two noncomplementary actions in the sequence /ʃs/ should render anticipation easier in the former cluster than in the latter. Differences in articulatory complexity between /sʃ/ and /ʃs/ may also explain why the latter sequence may show a longer duration and is often implemented through blending (i.e., an intermediate realization between /s/ and /ʃ/ throughout the entire cluster) or two successive articulatory targets, and even why the /ʃ/-related effects apply at the regressive level in the cluster /sʃ/ rather than at the progressive level in the cluster /ʃs/. Deviations from this production model could be attributed to language-dependent factors. One such factor has been identified in the present article: the trend for Western Catalan to favor the progressive assimilation of /ʃs/ into [(ʃ)ʃ] appears to be related to the fact that this dialect favors the progressive palatalization of /s/ after any alveolopalatal consonant, as for example in word-final consonant sequences such as /ɲs, ʎs, js/. This exceptional scenario resembles that of French where the articulatory adaptation between the two fricatives is more variable and less predictable than in English (in comparison to English, French shows less regressive assimilations for /sʃ/ and more progressive assimilations for /ʃs/; [Niebuhr et al., 2011]). Another interesting finding reported in the ‘Results’ section is a trend for /ʃs/ to approach /ʃ/ when stressed presumably as articulatory displacement, and thus tongue dorsum raising, for the /ʃ/ member of the cluster increases with degree of stress. This articulatory difference predicts precisely that, in comparison with the unstressed variant of /ʃs/, the stressed one will show more dorsopalatal contact and thus a lower EPG similarity index value, and also a lower COG spectral value associated with a larger front cavity size. The present study shows that articulatory as well as nonphonetic factors may account for the asymmetrical adaptation behavior exhibited by the sequences /sʃ/ and /ʃs/. It also corroborates the existence of categorical assimilation processes, i.e., the complete articulatory adaptation of /s/ to /ʃ/ in the cluster /sʃ/ in Eastern Catalan, and also in the case of the cluster /ʃs/ for some Western Catalan speakers. A productionbased model has been proposed in order to interpret the asymmetrical behavior of the two fricative consonant sequences which is based essentially on differences in articulatory complexity and coarticulatory resistance between the two lingual fricatives. Further research is needed in order to explore the relationship between segmental duration and the articulatory realization of /sʃ/ and /ʃs/ by taking into account a different set of experimental conditions from those used in the present investigation.

Acknowledgments This research was supported by project FFI2009-09339 of the Spanish Ministry of Science and Innovation and FEDER, by the ICREA Academia program, and by project 2009SGR3 of the Catalan Government. We would like to thank Leonardo Lancia for allowing us to use a MatLab script for computing COG values at successive temporal points during the frication noise, and two anonymous reviewers and the Associate Editor Oliver Niebuhr for their comments on a previous manuscript version.

Andrade, A.: [ʃ]-[s] accommodation in European Portuguese: an acoustic and perceptual study. Proc. 15th ICPhS, Barcelona 2003, pp. 3045–3049. Behrens, S.; Blumstein, S.E.: On the role of the amplitude of the fricative noise in the perception of place of articulation in voiceless fricative consonants. J. acoust. Soc. Am. 84: 861–867 (1988). Bonet, E.; Lloret, M.R.: Fonologia catalana (Ariel, Barcelona 1998). Browman, C.P.; Goldstein, L.: Articulatory gestures as phonological units. Phonology 6: 201–251 (1989). Browman, C.P.; Goldstein, L.: Representation and reality: physical systems and phonological structure. J. Phonet. 18: 411–424 (1990). Browman, C.P.; Goldstein, L.: Articulatory phonology: an overview. Phonetica 49: 155–180 (1992). Bybee, J.: Phonology and language use (Cambridge University Press, Cambridge 2001). Bybee, J.: Frequency of use and the organization of language (Oxford University Press, Oxford 2006). Cho, T.; Jun, S.-A.; Ladefoged, P.: Acoustic and aerodynamic correlates of Korean stops and fricatives. J. Phonet. 30: 193–228 (2002). Ellis, L.; Hardcastle, W.J.: An instrumental study of alveolar to velar assimilation in careful and fast speech. Proc. XIVth ICPhS, San Francisco 1999, pp. 2425–2428. Ellis, L.; Hardcastle, W.J.: Categorical and gradient properties of assimilation in alveolar to velar sequences: evidence from EPG and EMA data. J. Phonet. 30: 373–396 (2002). Farnetani, E.; Busà, M.G.: Italian clusters in continuous speech. Proc. 1994 Int. Conf. on Spoken Lang. Processing, Yokohama 1994, pp. 359–362. Fougeron, C.: Prosodically conditioned articulatory variation: a review. UCLA Working Papers Phonet. 97: 1–73 (1999). Guzik, K.M.; Harrington, J.: The quantification of place of articulation assimilation in electropalatographic data using the similarity index (SI). Adv. Speech Pathol. 9: 109–119 (2007). Hardcastle, W.J.; Jones, W.; Knight, C.; Trudgeon, A.; Calder, C.: New developments in electropalatography: a state-of-the-art report. Clin. Ling. Phonet. 3: 1–38 (1989). Holst, T.; Nolan, F.: The influence of syntactic structure on [s] to [ʃ] assimilation; in Connell, Arvaniti, Phonology and phonetic evidence. Papers in Laboratory Phonology IV, pp. 315–333 (Cambridge University Press, Cambridge 1995). Honoroff, D.N.: Articulatory gestures and Spanish nasal assimilation; PhD Yale University (1999). Jongman, A.; Wayland, R.; Wong, S.: Acoustic characteristics of English fricatives. J. acoust. Soc. Am. 108: 1252– 1263 (2000). Jun, J.: Perceptual and articulatory factors in place assimilation: an optimality theoretic approach. UCLA Occasional Papers in Linguistics 16, Dissertation Series 2 (1995). Kühnert, B.; Hoole, P.: Speaker-specific kinematic properties of alveolar reduction in English and German. Clin. Ling. Phonet. 18: 559–575 (2004). Ladefoged, P.; Maddieson, I.: The sounds of the world’s languages (Blackwell, Oxford 1996). Leite de Vasconcelos, J.: Esquisse d’une dialectologie portugaise (Aillaud, Paris 1901). Mateus, M.H.; d’Andrade, E.: The phonology of Portuguese (Oxford University Press, Oxford 2000). Narayanan, S.S.; Alwan, A.A.; Haker, K.: An articulatory study of fricative consonants using magnetic resonance imaging. J. acoust. Soc. Am. 98: 1325–1347 (1995). Nartey, J.N.A.: On fricative phones and phonemes. UCLA Working Papers Phonet. 55 (1982). Niebuhr, O.; Clayards, M.; Meunier, Ch.; Lancia, L.: On place assimilation in sibilant sequences – comparing French and English. J. Phonet. 39: 429–445 (2011). Niebuhr, O.; Meunier, Ch.: The phonetic manifestation of French /s#∫/ and /∫#s/ sequences in different vowel contexts: on the occurrence and the domain of sibilant assimilation. Phonetica 68: 1–28 (2011). Nolan, F.: The descriptive role of segments: evidence from assimilation; in Docherty, Ladd, Papers in Laboratory Phonology II, pp. 261–280 (Cambridge University Press, Cambridge 1992). Nolan, F.; Holst, T.; Kühnert, B.: Modelling [s] to [ʃ] accommodation in English. J. Phonet. 24: 113–137 (1996). Ohala, J.J.; Kawasaki, H.: Prosodic phonology and phonetics. Phonology 1: 113–128 (1984). Perkell, J.; Boyce, S.; Stevens, K.: Articulatory and acoustic correlates of the [s-ʃ] distinction; in Wolf, Klatt, 97th Meet. Acoust. Soc. Am., New York 1979, pp. 109–113.

Fricative Clusters /sʃ/ and /ʃs/ in Catalan

Phonetica 2013;70:298–322 DOI: 10.1159/000356628

321

Downloaded by: Siriraj Medical Library, Mahidol University 198.143.39.97 - 3/11/2016 7:57:26 PM

References

322

Phonetica 2013;70:298–322 DOI: 10.1159/000356628

Recasens/Mira

Downloaded by: Siriraj Medical Library, Mahidol University 198.143.39.97 - 3/11/2016 7:57:26 PM

Pouplier, M.; Hoole, P.; Scobbie, J.M.: Investigating the asymmetry of English sibilant assimilation: acoustic and EPG data. Lab. Phonol. 2: 1–33 (2011). Recasens, D.: Fonètica descriptiva del català: assaig de caracterizació de la pronúncia del vocalisme i consonantisme del català al segle XX; 2nd ed. (Institut d’Estudis Catalans, Barcelona 1996). Recasens, D.: Integrating coarticulation, ‘blending’ and assimilation into a model of articulatory constraints; in Goldstein, Whalen, Best, Laboratory Phonology 8, pp. 611–634 (Mouton de Gruyter, Berlin 2006). Recasens, D.: A study of jaw coarticulatory resistance and aggressiveness for Catalan consonants and vowels. J. acoust. Soc. Am. 132: 412–420 (2012). Recasens, D.; Espinosa, A.: An electropalatographic and acoustic study of affricates and fricatives in two Catalan dialects. J. int. phonet. Ass. 37: 143–172 (2007). Recasens, D.; Espinosa, A.: An articulatory investigation of lingual coarticulatory resistance and aggressiveness for consonants and vowels in Catalan. J. acoust. Soc. Am. 125: 2288–2298 (2009). Recasens, D.; Pallarès, M.D.; Fontdevila, J.: A model of lingual coarticulation based on articulatory constraints. J. acoust. Soc. Am. 102: 544–561 (1997). Solé, M.J.: Production requirements of apical trills and assimilatory behavior; in Ohala, Hasegawa, Ohala, Granville, Bailey, Proc. 14th Int. Congr. Phonet. Sci., University of California at Berkeley, San Francisco 1999, pp. 77–94. Solé, M.J.: Aerodynamic characteristics of trills and phonological patterning. J. Phonet. 30: 655–688 (2002). Soli, S.: Second formants in fricatives: acoustic consequences of fricative-vowel coarticulation. J. acoust. Soc. Am. 70: 976–984 (1981).