JOURNAL
OF COMML’NICATION
DISORDERS
11 (19781,
107-l 18
107
THE PERCEPTUAL USE OF SEMANTIC RULES BY NORMAL-HEARING AND HARD-OF-HEARING CHILDREN TERRY KENT LEWIS Universily
Hospital,
lJni\~ersity of Western Ontario
JOSEPH C. WILCOX’”
University ofWisconsin-Eau
Claire
This study investigated the effects of varying degrees of linguistic constraint upon the performance of hard-of-hearing subjects in a repetition task. Experimental stimuli consisted of three sets of sentence strings: grammatical, semantically anomalous, and ungrammatical, respectively. While the control group performed essentially equally across all three conditions, the hard-of-hearing group performed best to the grammatical stimuli and worst to the ungrammatical stimuli. It was hypothesized that the hard-of-hearing subjects employed a primitive sentence dictionary, while the normal-hearing subjects had developed a more sophisticated word dictionary.
Introduction The hard-of-hearing child is expected to differ from the hearing child in terms of language comprehension and production. He is also expected to differ from the hearing child in terms of vocabulary development. Few studies have dealt with these differences. Wilcox and Tobin (1974) studied the language of the hard-of-hearing child compared with that of the hearing child. They found that among their subjects, aged 9 to 12 years, the hard of hearing differed significantly in the production of certain verb constructions. These differences were determined to be ones of delay rather than of deviant development. This study did not assess comprehension, however. It only assessed production. It did not assess the use made of semantic rules in the formaton of sentences, but only assessed the use made of syntactic rules. Chomsky ( 1957, 1965) described a grammatical system in which a set of rules generates the surface form of a sentence from an underlying form. This set of rules included both syntactic and semantic rules. While the syntactic rules were described in detail, the semantic rules were described only as assigning meaning to the underlying structure of the sentence. The actual structure of the semantic
* Address correspondence to: Joseph C. Wilcox, Wisconsin, Eau Claire, Wisconsin 54701. D Elsevier North-Holland,
Inc.,
1978
Speech
and Hearing
Center,
University
0021.9924/78/0011-0107$01.75
of
108
TERRY
KENT LEWIS and JOSEPH C. WILCOX
component and the way in which meaning is derived from a sentence were not described completely. Katz ( 1966) described the function of the semantic rules as( 1) assigning meanings to underlying structures of a sentence, (2) assigning semantic interpretations to the syntactic constituents on the basis of the meanings assigned to the underlying structures, i.e., words and morphemes, and (3) assigning meaning to the sentence as a whole, based on the meanings assigned to the elements that make up the sentence. The semantic component of the grammar, in the mind of the speaker, was described as one in which words were listed with a set of concepts and a set of contextual restrictions. Each set of concepts and restrictions is unique to a particular word. The set of contextual restrictions includes syntactic-class markers, which signify the parts of speech that the word may assume, and the changes in meaning involved in assuming a particular part of speech. Semantic rules then combine the meanings of two or more words and morphemes of the base-structure, if the contextual restrictions associated with the meaning of the words allow for such combinations. This semantic structure described by Katz (1966) is a fully developed adult structure. A child’s semantic rule system is not expected to have the same form, or is it expected to be merely a reduced form of the adult model. The form of the child’s semantic structure is expected to change over time, so that it may develop into the adult form. Therefore, the semantic structure of the child’s grammar may differ from that of the adult, depending on the age at which it is observed. Menyuk (1969) described the process by which a child’s semantic system develops. During the early stages of development, syntax and semantics are interdependent. Many words have several meanings which are differentiated according to the syntactic context. Other words, such as pronouns, cannot be expressed, because the syntactic classes necessary for their expression have not yet developed. The acquisition of a new syntactic class allows for the addition of words to fill its place in sentences. The general pattern of development of a new syntactic class was described by Menyuk (1969) as (1) sentences are produced without the expression of the class, although the structure of the sentence makes the presence of the class mandatory, e.g., “Give _the clay;” (2) some members of the class appear before others and are substituted in some orderly way for all occurrences of the class, e.g., “It’s a good boy” and “It’s a nice daddy”; and (3) the members of the class are differentiated and new members added, e.g., “I want it the brush” and “I want it.” The substitutions seemed to be either the result of incomplete listings of concepts or of nonobservance of contextual restrictions. Thus, the general pattern of development seems to be that words are first undifferentiated and then later differentiated. The reason for such a pattern may be that the word entries are not
PERCEPTUAL
USE OF SEMANTIC
RULES
109
complete when first made into the child’s vocabulary. Later, the entries are completed and the words are fully differentiated. Words are not always acquired in such a fashion. At some time in his development, the child has the capacity to acquire new vocabulary entries without following this sequence. At that time, entries are made simply by observing the meaning of a new word or morpheme through contextual and syntactic content, and by applying a knowledge of the semantic rules incorporated into his language. This point of development represents the stage of transition to a mature adult-form of the grammar. This change from the child form to the adult form of the grammar was found to occur between the ages 5 and 8 years in normalhearing children (McNeill, 1970). McNeil1 (1970) described the development of the mature semantic structure in terms of a change from the earliest form-a sentence dictionary-to the mature form-a word dictionary. This description considered the first utterances of the child-single words-as representing one, or several, sentence meanings, e.g., the child’s utterance “ball” may mean “give me the ball,” “throw the ball,” “here is the ball,” and so forth. This would be the form of the child’s semantic structure: one word represents several sentence meanings. The adult semantic structure would list each word of the sentence separately, and the meaning of the sentence would be made up of a combination of the meanings of the words of which it is composed. The change from the child-form to the adult-form is the result of the development of a system of semantic markers (concepts associated with the meaning of words) and contextual restrictions (rules governing the use of words in combination with other words). The change, in simplest terms, is one from a system in which a word includes the meaning of one or several sentences, to one in which the word makes up a small part of the meaning of the sentence. The functions of the word, in the child’s system, are taken over by semantic rules in the adult system. It is assumed that the development from the child’s system to the adult’s system is the result of linguistic experience. Therefore, it is assumed that if that linguistic experience is severely limited, as in the case of hard-of-hearing children, then change from a child’s system to an adult’s system is delayed. Such a delay would be demonstrated as (1) ability to deal with sentences as a whole, but (2) inability to deal with words in combination as independent entities. Development of an adult form would be demonstrated as (1) ability to deal with sentences as a whole and (2) ability to deal with words in combination as independent entities. Miller and Isard (1963), Martin (1968)) Scholes (1969), and McNeil1 (1970) found that knowledge of both syntactic and semantic rules was necessary for correct perception of sentences. Subject’s use of those rules was measured as correct repetition of grammatical, semantically anomalous, and ungrammatical
TERRY KENT LEWIS and JOSEPH
110
C. WILCOX
sentences. These results were found for normal-hearing subjects, both children and adults. There have been no studies that have assessed the effects of these rules on the perception of hard-of-hearing subjects. Methodology This study examined the ability of hard-of-hearing children to imitate three kinds of sentences: grammatical, semantically anomalous, and ungrammatical. In order for the child to imitate the sentences correctly, he must structure his perception of the sentences according to semantic rules. The term “hard of hearing” as used in this study refers to the educational placement of the child. Thus, the hard-of-hearing child is differentiated from the deaf child, not by specific pure-tone thresholds, but by placement in a class for the hard of hearing as opposed to a class for the deaf. The term hard of hearing then reflects the child’s educational achievement and communication problems as demonstrated during several years of formal instruction in public schools. Stimulus Sentences A set of 30 sentences was constructed in the manner described by Miller and Isard (1963). There were 10 each of grammatical, semantically anomalous, and ungrammatical sentences. Each sentence contained five content words. Syntactic constructions which may not be within the knowledge of a hard-of-hearing child were excluded (Wilcox and Tobin, 1974). The vocabulary was controlled for simplicity and commonality. All words were chosen from a list of the 2000 most commonly occurring words, as compiled by Thorndike (1932). Experimental
Task
Subjects were required to imitate the stimulus sentence. Instructions were that the subject would hear a group of sentences, some which made sense, some which made little sense, and some which made no sense, and that his task was to repeat the sentence immediately after hearing it. An imitation task was selected as a means of determining whether or not subjects correctly heard a sentence. Such a task was reported to be well within the ability of a child (McNeill, 1970, p. 118). Listening
Control in Sound Field
The hard-of-hearing children in this study were wearing hearing aids. Therefore, testing was carried out in a sound field. In order to control the level of presentation to each subject, a uniform distance was maintained at all times between the hearing aid microphone and the speaker of the tape recorder used for stimulus presentation. This distance was 18 inches (West et al., 1957, p. 662).
PERCEPTUAL
USE OF SEMANTIC
RULES
111
Stimulus Presentation The experimental tape, recorded on a Magnecord tape recorder model 1022, consisted of the following: (1) speech detection threshold words, (2) calibration noise, (3) speech discrimination test words, and (4) stimulus sentences. The test words were delivered at a level of 40-dB Sensation Level. This level was determined empirically by varying the gain control of the tape recorder until the subject could just barely detect the presence of the test words. The gain control setting at this point was considered to represent the subject’s speech detection threshold. The tape was then advancead to the noise section and the output was monitored on a Hewlett-Packard r.m.s. volt meter. The gain of the tape recorder was raised until the volt meter registered a change of 40 dB. The test words and discrimination words were presented at that level. Subjects’ responses were recorded on a Uher Universal 5000 tape recorder.
Selection of Subjects Subjects were selected from the hard-of-hearing classes of a public school program for the hearing impaired. Criteria for selection was achieving a discrimination score of 50% or higher. Bilingual subjects and subjects who spoke a dialect different from that of the speaker on the experimental tape were excluded. Ten experimental subjects were selected from an age range of 9 to 14 years old, with a mean of 12 years. Hearing loss ranged from 50 to 89 dB with a mean of 67.8 dB (pure-tone averages for 500, 1000, and 2000 Hz). For each experimental subject, a matching control subject was selected from the normal-hearing population of the same school. Results and Discussion This study attempted to determine whether or not there is a difference between the use made of semantic rules in the perception of speech by hard-of-hearing and normal-hearing children and what indications the use, or lack of use, of such rules had for the stage of semantic development of each group of children.
Collection of Data Responses of subjects to the stimulus sentences were tape recorded and scored independently by six experienced judges. Criteria for correct response were: (1) that the words appeared in the correct order, relative to other words repeated; (2) that any word scored correct be present in the response; (3) that the word repeated be correct in its basic form, but that mistakes in grammatical endings not be counted as errors.
112
TERRY KENT LEWIS and JOSEPH
Reliability
C. WILCOX
of Judges
A range of 0.8 words per response, on the average, was found among judges. Because of this variability, a Spearman-Brown prophecy formula was administered to the data. Reliability among judges was calculated for each sentence type. Reliability coefficients were found of 0.98 for the grammatical and semantically anomalous sentences and of 0.87 for the ungrammatical sentences. Thus, substantial agreement was obtained on all sentence types. Therefore, the ratings of the judges were pooled for each sentence type for each subject. Analysis
of Results
The data were analyzed, using a two-factor plot design with repeated measures (Kirk, 1968). A summary of this analysis is shown in Table 1. Both hearing status and sentence type significantly affected performance, as did the interaction between hearing status and sentence type. An analysis of variance of the simple main affects was then performed. The results of this analysis are shown in Table 2. Analysis of the between-subjects variance indicated that the experimental and control groups differed from each other for each of the three sentence types with the normal-hearing subjects performing consistently better than the hearingimpaired group. This difference can be seen in Fig. 1. Analysis of within-subjects variance revealed that the hearing-impaired subjects performed differently across sentence types, while no such difference was observed for the normal-hearing subjects. Figure 2 shows a graphic representation of these findings. For the hard-of-hearing group, performance was best for the grammatical sentences and worst for the ungrammatical strings. The normal-hearing group performed at essentially the same level for each of the three sentence types. Pairwise comparisons between the means for the hearing-impaired group confirmed that differences observed in Fig. 2 are statistically significant. Similarly, pairwise comparison procedure revealed that the normal-hearing group’s performance for the grammatical sentences was not statistically different from their performance on the other two sentence types. Correlations
with Related Variables
Correlations were calculated between (1) degree of hearing loss and performance on each type of sentence; (2) degree of loss and discrimination scores; (3) discrimination scores and performance for each sentence type; and (4) number of years in school and each sentence type. These were calculated using the Spearman rank order correlation coefficient. The only correlations found to be sig-
PERCEPTUAL
Analysis
of Variance
Source
USE OF SEMANTIC
RULES
113
TABLE 1 of the Effects of Three Sentence Types upon the Repetition Hard-of-Hearing and Normal-Hearing Children ss
df
Between subjects
147.43
19
A (hearing status) Subj. w. groups Within subjects B (sentence type) AXB B X subj. w. groups
101.14 46.29 8.11 3.47 1.07 3.51
1 18 40 2 2 36
Total
155.54
59
Performance
MS
F
101.14 2.51 1.74 0.54 0.10
39.35 a 17.40n 5.40” -
of
-
-
-
nP i 0.01.
nificant were those between discrimination scores and performance the sentence types. These correlations can be seen in Table 3.
for each of
Types of Errors
The grammatical sentences were constructed on some variation of the form subject, verb, modifier, modifier, object. Errors on grammatical sentences usually involved omission of one or both of the modifiers. Errors rarely involved alteration of the word order or meaning of the sentences. A typical example of stimulus and error response is: “The hunter shot the huge growling bear”(stimulus) and “The hunter shot the bear” (response).
Analysis
of Variance
Source
Between subjects Between A at bi Between A at bz Between A at b3 Within cell Within subjects Between B at ai Between B at a2 AB B X subj. w. groups Total OP < 0.01.
TABLE 2 for Simple Main Effects of Three Sentence Types upon the Repetition mance of Hard-of-Hearing and Normal-Hearing Subjects ss
df
-
-
MS -
27.15 31.25 43.81 49.86
1 1 1 54
27.15 31.25 43.81 0.92
4.05 0.48 1.07 3.57
2 2 2 36
2.03 0.24 0.54 0.10
155.54
59
-
Perfor-
F 29.51 ’ 33.970 47.62 a 20.30a 2.40 5.400 -
114
TERRY KENT LEWIS and JOSEPH
C. WILCOX
100, 00
Grammatical
M
Semantically Anomalous
A-A
Ungrammatical
90,
80,
70_
60_
Normal
Hearing
Hearing
Impaired
Analysis of between subjects variance of the effects of three different sentence types upon Fig. 1. the repetition performance of hard-of-hearing and nomat-hearing children.
Errors on the semantically anomalous sentences involved omission of words and substitution of words. Fewer words were repeated in response. Many of the errors involved alterations of the stimulus sentence, which resulted in a response that more closely resembled a grammatical sentence than did the stimulus sentence. A typical example is: “A newspaper signed the bright birthday bear” (stimulus) and “Bear birthday bright sells newspapers” (response). Errors on the ungrammatical sentences involved omission of words and alteration of sentences. All responses were short. Alterations resulted in sentences that more closely resembled grammatical sentences. In general, errors on semantically anomalous and ungrammatical sentences were the same for the hard-of-hearing subjects, but were different on the grammatical sentences. These error responses can be interpreted as an attempt to hear grammatical sentences in any utterance. Thus, the hard-of-hearing subjects at-
PERCETTUAL
USE OF SEMANTIC
0-0
Normal
Hearing
Cl-El
Hearing
Impaired
RULES
115
100
90
80
70
60
50
40 t i! s 30 E E 20 iii n 10
0 Ungram
Fig. 2. Analysis upon the repetition
Sem Anom
Gram
of within subjects variance of the effects of three different sentence types performance of hard-of-hearing children.
tempted to respond to all sentences with grammatical responses, contrary to instructions given them, and thus, they made more and more errors as the stimulus sentences deviated from a grammatical model. Relation of Discrimination
to Peiformance
A correlation was found between discrimination and performance across sentence types for the hard-of-hearing subjects. The near-normal group obtained discrimination scores in the 80% range, the middle group in the 60 to 70% range, and the low group in the 50% range. The correlation between discrimination scores and level of performance might suggest that subjects performed poorly only because they did not understand the
116
TERRY KENT LEWIS and JOSEPH
Correlations
between Performance
Scores,
TABLE 3 Amount of Hearing Loss, and Discrimination
Scores P
Variable Degree of loss Degree of loss Degree of loss Degree of loss Discrimination Discrimination Discrimination a Significant
C. WILCOX
vs. vs. vs. vs. vs. vs. vs.
discrimination performance performance performance performance performance performance
(gramm.) (sem. anom.) (ungramm.) (gramm) (sem. anom.) (ungramm.)
0.41 0.37 0.33 0.32 0.99” 0.98 a 0.99”
at 0.01 level.
words used in the stimulus sentences. However the vocabulary was the same across sentence types. Therefore, it seems likely that another explanation would better account for the observed differences in performances and for the correlation between discrimination and performance. A possible explanation is that the hard-of-hearing subjects applied a primitive semantic rule system (sentence dictionary) to their perception of the stimulus sentences. They applied this form of semantic description to all sentences, although they were instructed that few of the sentences were meaningful. It seemed as though they could not do otherwise than to apply semantic rules that treated all utterances as sentences. Thus, they displayed an inability to deal with words in combination as independent entities, but they demonstrated an ability to deal with sentences. The discrimination ability of each subject was directly related to his delayed development. The more limited the subject’s ability to discriminate words, the more delayed was his semantic development. The normal-hearing and near-normal hard-of-hearing subjects had high discrimination scores; therefore, their semantic development had proceded normally. Thus, at the time of this study, they applied a mature semantic structure (word dictionary) to their perception of the stimulus sentences. And they demonstrated an ability to deal with words in combination as independent entities. Semantic Development The results of this study suggest a regular sequence of semantic development. The theories of Katz (1966), Menyuk (1969)) and McNeil1 (1970) suggested that the development of semantic rules is closely related to the development of syntactic rules. The semantic rule system appears to begin as a sentence dictionary at the syntactic level of holophrastic word utterances. Each sentence is a word, and meaning is available only for the sentence as a whole. Thus, the child’s utterance “milk” may represent many meanings, depending on the situational context in
PERCEPTUAL USE OF SEMANTIC RULES
117
which it is uttered. The child may be saying “I want some milk” or “There is some milk. ” However, no meaning would be available for the word milk that would correspond to “a white liquid obtained from mammary glands. ” The second stage of semantic development involves the expansion of the syntactic rule system. More and more sentence constructions are developed as the child progresses from holophrastic words to transformations. Word order becomes important. The child’s use of more and more complex syntax results in sentences being constructed that contrast meaning on the basis of subtle word orders, and more and more ambiguous sentences are formed. The child finds his sentence dictionary becoming more and more inefficient as he tries to store all of this information in his memory. The third stage of development involves the emergence of a word dictionary, as the result of the inefficiency of the sentence dictionary. As a result of this development, meaning can be applied to isolated words and to words in combination. Thus, word meanings are stored and the appropriate meaning for each word contributes to the meaning for the entire sentence. The normal-hearing and near-normal hard-of-hearing subjects exhibited a word dictionary. The middle and low groups of hard-of-hearing subjects exhibited a sentence dictionary. These subjects attempted to respond to all sentences with a grammatical response. They tended to avoid the semantically anomalous and ungrammatical sentences. A possible explanation is that they could not assign meaning to the sentences (by definition they have no meaning). Nor could they assign meaning to the words of the sentence as independent entities. Wilcox and Tobin (1974) found the same type of response among hard-ofhearing children in the course of a study of syntactic development. The findings of this study would suggest that present educational programs are not adequate for 80% of the hard-of-hearing children enrolled in them, that is, they do not treat the children according to their discrimination ability, but only according to their pure-tone losses. This type of classification seems to be adequate for about 2OY6 of the children examined in this study, but the other 80% suffer greatly in terms of delayed language development. A more beneficial program might be one in which the children are directed into an early program that would allow their language to develop unaffected by their limited discrimination ability, such as a manual or combined program. Then, at a later age, when they had already started using complex language, the children could be directed into a basically oral or manual program. A language development program which followed the course of what is described herein as the normal stages of semantic development might also be more beneficial. It seems to these authors that the purpose of the language training provided these children is not to further their vocabulary development per se so much as to force their internal language structure to change in as normal a way as possible. The language training should be directed toward making the child’s
118
TERRY KENT LEWIS and JOSEPH
C. WILCOX
primitive grammatical description progressively more ambiguous so that it eventually becomes useless, so that, following the natural order of language development, he will acquire a mature rule system. References Chomsky, N. Synfncric srructures. The Hague: Mouton and Co., 1957. Chomsky, N. Aspects of the theory of syntax. Cambridge, Mass.: M.I.T. Press, 1965. Dirk, R. Experimental design procedures for the behavioral sciences. Belmont, Calif.: Wadsworth Publ. Co., 1968. Katz, J.The philosophy of language. New York: Harper & Row, 1966. Martin, J. A comparison of ordinary, anomalous, and scrambled strings. J. Verb. Learning Verb. Behav. 1968, 7, 390-395. McNeill, D. The acquisition of language: the study of developmental psycholinguistics. New York: Harper & Row, 1970. Menyuk, P. Sentences children use. Cambridge, Mass.: M.I.T. Press, 1969. Miller, Cl., Isard, S. Some perceptual consequences of linguistic rules. J. Verb. Learning Verb. Behav. , 1963,2, 217-228. Scholes, R. The role of grammaticality in the imitation of word strings by children and adults. J. Verb. Learning Verb. Behav., 1969, 8, 289-294. Thorndike, E. A teacher’s word book of the twenty thousand wordsfound mostfrequently and widely in general reading for children and young people. New York: Bureau of Publications, Teacher’s College, Columbia University, 1932. West, R., Ansbemy, M., Carr, A. The rehabilitation of speech. New York: Harper & Brothers, 1957. Wilcox, J., Tobin, H. Linguistic performance of hard-of-hearing and normal hearing children. J. Speech Hear. Res., 1974, 17, 286-293.
OF COMML’NICATION
DISORDERS
11 (19781,
107-l 18
107
THE PERCEPTUAL USE OF SEMANTIC RULES BY NORMAL-HEARING AND HARD-OF-HEARING CHILDREN TERRY KENT LEWIS Universily
Hospital,
lJni\~ersity of Western Ontario
JOSEPH C. WILCOX’”
University ofWisconsin-Eau
Claire
This study investigated the effects of varying degrees of linguistic constraint upon the performance of hard-of-hearing subjects in a repetition task. Experimental stimuli consisted of three sets of sentence strings: grammatical, semantically anomalous, and ungrammatical, respectively. While the control group performed essentially equally across all three conditions, the hard-of-hearing group performed best to the grammatical stimuli and worst to the ungrammatical stimuli. It was hypothesized that the hard-of-hearing subjects employed a primitive sentence dictionary, while the normal-hearing subjects had developed a more sophisticated word dictionary.
Introduction The hard-of-hearing child is expected to differ from the hearing child in terms of language comprehension and production. He is also expected to differ from the hearing child in terms of vocabulary development. Few studies have dealt with these differences. Wilcox and Tobin (1974) studied the language of the hard-of-hearing child compared with that of the hearing child. They found that among their subjects, aged 9 to 12 years, the hard of hearing differed significantly in the production of certain verb constructions. These differences were determined to be ones of delay rather than of deviant development. This study did not assess comprehension, however. It only assessed production. It did not assess the use made of semantic rules in the formaton of sentences, but only assessed the use made of syntactic rules. Chomsky ( 1957, 1965) described a grammatical system in which a set of rules generates the surface form of a sentence from an underlying form. This set of rules included both syntactic and semantic rules. While the syntactic rules were described in detail, the semantic rules were described only as assigning meaning to the underlying structure of the sentence. The actual structure of the semantic
* Address correspondence to: Joseph C. Wilcox, Wisconsin, Eau Claire, Wisconsin 54701. D Elsevier North-Holland,
Inc.,
1978
Speech
and Hearing
Center,
University
0021.9924/78/0011-0107$01.75
of
108
TERRY
KENT LEWIS and JOSEPH C. WILCOX
component and the way in which meaning is derived from a sentence were not described completely. Katz ( 1966) described the function of the semantic rules as( 1) assigning meanings to underlying structures of a sentence, (2) assigning semantic interpretations to the syntactic constituents on the basis of the meanings assigned to the underlying structures, i.e., words and morphemes, and (3) assigning meaning to the sentence as a whole, based on the meanings assigned to the elements that make up the sentence. The semantic component of the grammar, in the mind of the speaker, was described as one in which words were listed with a set of concepts and a set of contextual restrictions. Each set of concepts and restrictions is unique to a particular word. The set of contextual restrictions includes syntactic-class markers, which signify the parts of speech that the word may assume, and the changes in meaning involved in assuming a particular part of speech. Semantic rules then combine the meanings of two or more words and morphemes of the base-structure, if the contextual restrictions associated with the meaning of the words allow for such combinations. This semantic structure described by Katz (1966) is a fully developed adult structure. A child’s semantic rule system is not expected to have the same form, or is it expected to be merely a reduced form of the adult model. The form of the child’s semantic structure is expected to change over time, so that it may develop into the adult form. Therefore, the semantic structure of the child’s grammar may differ from that of the adult, depending on the age at which it is observed. Menyuk (1969) described the process by which a child’s semantic system develops. During the early stages of development, syntax and semantics are interdependent. Many words have several meanings which are differentiated according to the syntactic context. Other words, such as pronouns, cannot be expressed, because the syntactic classes necessary for their expression have not yet developed. The acquisition of a new syntactic class allows for the addition of words to fill its place in sentences. The general pattern of development of a new syntactic class was described by Menyuk (1969) as (1) sentences are produced without the expression of the class, although the structure of the sentence makes the presence of the class mandatory, e.g., “Give _the clay;” (2) some members of the class appear before others and are substituted in some orderly way for all occurrences of the class, e.g., “It’s a good boy” and “It’s a nice daddy”; and (3) the members of the class are differentiated and new members added, e.g., “I want it the brush” and “I want it.” The substitutions seemed to be either the result of incomplete listings of concepts or of nonobservance of contextual restrictions. Thus, the general pattern of development seems to be that words are first undifferentiated and then later differentiated. The reason for such a pattern may be that the word entries are not
PERCEPTUAL
USE OF SEMANTIC
RULES
109
complete when first made into the child’s vocabulary. Later, the entries are completed and the words are fully differentiated. Words are not always acquired in such a fashion. At some time in his development, the child has the capacity to acquire new vocabulary entries without following this sequence. At that time, entries are made simply by observing the meaning of a new word or morpheme through contextual and syntactic content, and by applying a knowledge of the semantic rules incorporated into his language. This point of development represents the stage of transition to a mature adult-form of the grammar. This change from the child form to the adult form of the grammar was found to occur between the ages 5 and 8 years in normalhearing children (McNeill, 1970). McNeil1 (1970) described the development of the mature semantic structure in terms of a change from the earliest form-a sentence dictionary-to the mature form-a word dictionary. This description considered the first utterances of the child-single words-as representing one, or several, sentence meanings, e.g., the child’s utterance “ball” may mean “give me the ball,” “throw the ball,” “here is the ball,” and so forth. This would be the form of the child’s semantic structure: one word represents several sentence meanings. The adult semantic structure would list each word of the sentence separately, and the meaning of the sentence would be made up of a combination of the meanings of the words of which it is composed. The change from the child-form to the adult-form is the result of the development of a system of semantic markers (concepts associated with the meaning of words) and contextual restrictions (rules governing the use of words in combination with other words). The change, in simplest terms, is one from a system in which a word includes the meaning of one or several sentences, to one in which the word makes up a small part of the meaning of the sentence. The functions of the word, in the child’s system, are taken over by semantic rules in the adult system. It is assumed that the development from the child’s system to the adult’s system is the result of linguistic experience. Therefore, it is assumed that if that linguistic experience is severely limited, as in the case of hard-of-hearing children, then change from a child’s system to an adult’s system is delayed. Such a delay would be demonstrated as (1) ability to deal with sentences as a whole, but (2) inability to deal with words in combination as independent entities. Development of an adult form would be demonstrated as (1) ability to deal with sentences as a whole and (2) ability to deal with words in combination as independent entities. Miller and Isard (1963), Martin (1968)) Scholes (1969), and McNeil1 (1970) found that knowledge of both syntactic and semantic rules was necessary for correct perception of sentences. Subject’s use of those rules was measured as correct repetition of grammatical, semantically anomalous, and ungrammatical
TERRY KENT LEWIS and JOSEPH
110
C. WILCOX
sentences. These results were found for normal-hearing subjects, both children and adults. There have been no studies that have assessed the effects of these rules on the perception of hard-of-hearing subjects. Methodology This study examined the ability of hard-of-hearing children to imitate three kinds of sentences: grammatical, semantically anomalous, and ungrammatical. In order for the child to imitate the sentences correctly, he must structure his perception of the sentences according to semantic rules. The term “hard of hearing” as used in this study refers to the educational placement of the child. Thus, the hard-of-hearing child is differentiated from the deaf child, not by specific pure-tone thresholds, but by placement in a class for the hard of hearing as opposed to a class for the deaf. The term hard of hearing then reflects the child’s educational achievement and communication problems as demonstrated during several years of formal instruction in public schools. Stimulus Sentences A set of 30 sentences was constructed in the manner described by Miller and Isard (1963). There were 10 each of grammatical, semantically anomalous, and ungrammatical sentences. Each sentence contained five content words. Syntactic constructions which may not be within the knowledge of a hard-of-hearing child were excluded (Wilcox and Tobin, 1974). The vocabulary was controlled for simplicity and commonality. All words were chosen from a list of the 2000 most commonly occurring words, as compiled by Thorndike (1932). Experimental
Task
Subjects were required to imitate the stimulus sentence. Instructions were that the subject would hear a group of sentences, some which made sense, some which made little sense, and some which made no sense, and that his task was to repeat the sentence immediately after hearing it. An imitation task was selected as a means of determining whether or not subjects correctly heard a sentence. Such a task was reported to be well within the ability of a child (McNeill, 1970, p. 118). Listening
Control in Sound Field
The hard-of-hearing children in this study were wearing hearing aids. Therefore, testing was carried out in a sound field. In order to control the level of presentation to each subject, a uniform distance was maintained at all times between the hearing aid microphone and the speaker of the tape recorder used for stimulus presentation. This distance was 18 inches (West et al., 1957, p. 662).
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111
Stimulus Presentation The experimental tape, recorded on a Magnecord tape recorder model 1022, consisted of the following: (1) speech detection threshold words, (2) calibration noise, (3) speech discrimination test words, and (4) stimulus sentences. The test words were delivered at a level of 40-dB Sensation Level. This level was determined empirically by varying the gain control of the tape recorder until the subject could just barely detect the presence of the test words. The gain control setting at this point was considered to represent the subject’s speech detection threshold. The tape was then advancead to the noise section and the output was monitored on a Hewlett-Packard r.m.s. volt meter. The gain of the tape recorder was raised until the volt meter registered a change of 40 dB. The test words and discrimination words were presented at that level. Subjects’ responses were recorded on a Uher Universal 5000 tape recorder.
Selection of Subjects Subjects were selected from the hard-of-hearing classes of a public school program for the hearing impaired. Criteria for selection was achieving a discrimination score of 50% or higher. Bilingual subjects and subjects who spoke a dialect different from that of the speaker on the experimental tape were excluded. Ten experimental subjects were selected from an age range of 9 to 14 years old, with a mean of 12 years. Hearing loss ranged from 50 to 89 dB with a mean of 67.8 dB (pure-tone averages for 500, 1000, and 2000 Hz). For each experimental subject, a matching control subject was selected from the normal-hearing population of the same school. Results and Discussion This study attempted to determine whether or not there is a difference between the use made of semantic rules in the perception of speech by hard-of-hearing and normal-hearing children and what indications the use, or lack of use, of such rules had for the stage of semantic development of each group of children.
Collection of Data Responses of subjects to the stimulus sentences were tape recorded and scored independently by six experienced judges. Criteria for correct response were: (1) that the words appeared in the correct order, relative to other words repeated; (2) that any word scored correct be present in the response; (3) that the word repeated be correct in its basic form, but that mistakes in grammatical endings not be counted as errors.
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Reliability
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of Judges
A range of 0.8 words per response, on the average, was found among judges. Because of this variability, a Spearman-Brown prophecy formula was administered to the data. Reliability among judges was calculated for each sentence type. Reliability coefficients were found of 0.98 for the grammatical and semantically anomalous sentences and of 0.87 for the ungrammatical sentences. Thus, substantial agreement was obtained on all sentence types. Therefore, the ratings of the judges were pooled for each sentence type for each subject. Analysis
of Results
The data were analyzed, using a two-factor plot design with repeated measures (Kirk, 1968). A summary of this analysis is shown in Table 1. Both hearing status and sentence type significantly affected performance, as did the interaction between hearing status and sentence type. An analysis of variance of the simple main affects was then performed. The results of this analysis are shown in Table 2. Analysis of the between-subjects variance indicated that the experimental and control groups differed from each other for each of the three sentence types with the normal-hearing subjects performing consistently better than the hearingimpaired group. This difference can be seen in Fig. 1. Analysis of within-subjects variance revealed that the hearing-impaired subjects performed differently across sentence types, while no such difference was observed for the normal-hearing subjects. Figure 2 shows a graphic representation of these findings. For the hard-of-hearing group, performance was best for the grammatical sentences and worst for the ungrammatical strings. The normal-hearing group performed at essentially the same level for each of the three sentence types. Pairwise comparisons between the means for the hearing-impaired group confirmed that differences observed in Fig. 2 are statistically significant. Similarly, pairwise comparison procedure revealed that the normal-hearing group’s performance for the grammatical sentences was not statistically different from their performance on the other two sentence types. Correlations
with Related Variables
Correlations were calculated between (1) degree of hearing loss and performance on each type of sentence; (2) degree of loss and discrimination scores; (3) discrimination scores and performance for each sentence type; and (4) number of years in school and each sentence type. These were calculated using the Spearman rank order correlation coefficient. The only correlations found to be sig-
PERCEPTUAL
Analysis
of Variance
Source
USE OF SEMANTIC
RULES
113
TABLE 1 of the Effects of Three Sentence Types upon the Repetition Hard-of-Hearing and Normal-Hearing Children ss
df
Between subjects
147.43
19
A (hearing status) Subj. w. groups Within subjects B (sentence type) AXB B X subj. w. groups
101.14 46.29 8.11 3.47 1.07 3.51
1 18 40 2 2 36
Total
155.54
59
Performance
MS
F
101.14 2.51 1.74 0.54 0.10
39.35 a 17.40n 5.40” -
of
-
-
-
nP i 0.01.
nificant were those between discrimination scores and performance the sentence types. These correlations can be seen in Table 3.
for each of
Types of Errors
The grammatical sentences were constructed on some variation of the form subject, verb, modifier, modifier, object. Errors on grammatical sentences usually involved omission of one or both of the modifiers. Errors rarely involved alteration of the word order or meaning of the sentences. A typical example of stimulus and error response is: “The hunter shot the huge growling bear”(stimulus) and “The hunter shot the bear” (response).
Analysis
of Variance
Source
Between subjects Between A at bi Between A at bz Between A at b3 Within cell Within subjects Between B at ai Between B at a2 AB B X subj. w. groups Total OP < 0.01.
TABLE 2 for Simple Main Effects of Three Sentence Types upon the Repetition mance of Hard-of-Hearing and Normal-Hearing Subjects ss
df
-
-
MS -
27.15 31.25 43.81 49.86
1 1 1 54
27.15 31.25 43.81 0.92
4.05 0.48 1.07 3.57
2 2 2 36
2.03 0.24 0.54 0.10
155.54
59
-
Perfor-
F 29.51 ’ 33.970 47.62 a 20.30a 2.40 5.400 -
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100, 00
Grammatical
M
Semantically Anomalous
A-A
Ungrammatical
90,
80,
70_
60_
Normal
Hearing
Hearing
Impaired
Analysis of between subjects variance of the effects of three different sentence types upon Fig. 1. the repetition performance of hard-of-hearing and nomat-hearing children.
Errors on the semantically anomalous sentences involved omission of words and substitution of words. Fewer words were repeated in response. Many of the errors involved alterations of the stimulus sentence, which resulted in a response that more closely resembled a grammatical sentence than did the stimulus sentence. A typical example is: “A newspaper signed the bright birthday bear” (stimulus) and “Bear birthday bright sells newspapers” (response). Errors on the ungrammatical sentences involved omission of words and alteration of sentences. All responses were short. Alterations resulted in sentences that more closely resembled grammatical sentences. In general, errors on semantically anomalous and ungrammatical sentences were the same for the hard-of-hearing subjects, but were different on the grammatical sentences. These error responses can be interpreted as an attempt to hear grammatical sentences in any utterance. Thus, the hard-of-hearing subjects at-
PERCETTUAL
USE OF SEMANTIC
0-0
Normal
Hearing
Cl-El
Hearing
Impaired
RULES
115
100
90
80
70
60
50
40 t i! s 30 E E 20 iii n 10
0 Ungram
Fig. 2. Analysis upon the repetition
Sem Anom
Gram
of within subjects variance of the effects of three different sentence types performance of hard-of-hearing children.
tempted to respond to all sentences with grammatical responses, contrary to instructions given them, and thus, they made more and more errors as the stimulus sentences deviated from a grammatical model. Relation of Discrimination
to Peiformance
A correlation was found between discrimination and performance across sentence types for the hard-of-hearing subjects. The near-normal group obtained discrimination scores in the 80% range, the middle group in the 60 to 70% range, and the low group in the 50% range. The correlation between discrimination scores and level of performance might suggest that subjects performed poorly only because they did not understand the
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TERRY KENT LEWIS and JOSEPH
Correlations
between Performance
Scores,
TABLE 3 Amount of Hearing Loss, and Discrimination
Scores P
Variable Degree of loss Degree of loss Degree of loss Degree of loss Discrimination Discrimination Discrimination a Significant
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vs. vs. vs. vs. vs. vs. vs.
discrimination performance performance performance performance performance performance
(gramm.) (sem. anom.) (ungramm.) (gramm) (sem. anom.) (ungramm.)
0.41 0.37 0.33 0.32 0.99” 0.98 a 0.99”
at 0.01 level.
words used in the stimulus sentences. However the vocabulary was the same across sentence types. Therefore, it seems likely that another explanation would better account for the observed differences in performances and for the correlation between discrimination and performance. A possible explanation is that the hard-of-hearing subjects applied a primitive semantic rule system (sentence dictionary) to their perception of the stimulus sentences. They applied this form of semantic description to all sentences, although they were instructed that few of the sentences were meaningful. It seemed as though they could not do otherwise than to apply semantic rules that treated all utterances as sentences. Thus, they displayed an inability to deal with words in combination as independent entities, but they demonstrated an ability to deal with sentences. The discrimination ability of each subject was directly related to his delayed development. The more limited the subject’s ability to discriminate words, the more delayed was his semantic development. The normal-hearing and near-normal hard-of-hearing subjects had high discrimination scores; therefore, their semantic development had proceded normally. Thus, at the time of this study, they applied a mature semantic structure (word dictionary) to their perception of the stimulus sentences. And they demonstrated an ability to deal with words in combination as independent entities. Semantic Development The results of this study suggest a regular sequence of semantic development. The theories of Katz (1966), Menyuk (1969)) and McNeil1 (1970) suggested that the development of semantic rules is closely related to the development of syntactic rules. The semantic rule system appears to begin as a sentence dictionary at the syntactic level of holophrastic word utterances. Each sentence is a word, and meaning is available only for the sentence as a whole. Thus, the child’s utterance “milk” may represent many meanings, depending on the situational context in
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117
which it is uttered. The child may be saying “I want some milk” or “There is some milk. ” However, no meaning would be available for the word milk that would correspond to “a white liquid obtained from mammary glands. ” The second stage of semantic development involves the expansion of the syntactic rule system. More and more sentence constructions are developed as the child progresses from holophrastic words to transformations. Word order becomes important. The child’s use of more and more complex syntax results in sentences being constructed that contrast meaning on the basis of subtle word orders, and more and more ambiguous sentences are formed. The child finds his sentence dictionary becoming more and more inefficient as he tries to store all of this information in his memory. The third stage of development involves the emergence of a word dictionary, as the result of the inefficiency of the sentence dictionary. As a result of this development, meaning can be applied to isolated words and to words in combination. Thus, word meanings are stored and the appropriate meaning for each word contributes to the meaning for the entire sentence. The normal-hearing and near-normal hard-of-hearing subjects exhibited a word dictionary. The middle and low groups of hard-of-hearing subjects exhibited a sentence dictionary. These subjects attempted to respond to all sentences with a grammatical response. They tended to avoid the semantically anomalous and ungrammatical sentences. A possible explanation is that they could not assign meaning to the sentences (by definition they have no meaning). Nor could they assign meaning to the words of the sentence as independent entities. Wilcox and Tobin (1974) found the same type of response among hard-ofhearing children in the course of a study of syntactic development. The findings of this study would suggest that present educational programs are not adequate for 80% of the hard-of-hearing children enrolled in them, that is, they do not treat the children according to their discrimination ability, but only according to their pure-tone losses. This type of classification seems to be adequate for about 2OY6 of the children examined in this study, but the other 80% suffer greatly in terms of delayed language development. A more beneficial program might be one in which the children are directed into an early program that would allow their language to develop unaffected by their limited discrimination ability, such as a manual or combined program. Then, at a later age, when they had already started using complex language, the children could be directed into a basically oral or manual program. A language development program which followed the course of what is described herein as the normal stages of semantic development might also be more beneficial. It seems to these authors that the purpose of the language training provided these children is not to further their vocabulary development per se so much as to force their internal language structure to change in as normal a way as possible. The language training should be directed toward making the child’s
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primitive grammatical description progressively more ambiguous so that it eventually becomes useless, so that, following the natural order of language development, he will acquire a mature rule system. References Chomsky, N. Synfncric srructures. The Hague: Mouton and Co., 1957. Chomsky, N. Aspects of the theory of syntax. Cambridge, Mass.: M.I.T. Press, 1965. Dirk, R. Experimental design procedures for the behavioral sciences. Belmont, Calif.: Wadsworth Publ. Co., 1968. Katz, J.The philosophy of language. New York: Harper & Row, 1966. Martin, J. A comparison of ordinary, anomalous, and scrambled strings. J. Verb. Learning Verb. Behav. 1968, 7, 390-395. McNeill, D. The acquisition of language: the study of developmental psycholinguistics. New York: Harper & Row, 1970. Menyuk, P. Sentences children use. Cambridge, Mass.: M.I.T. Press, 1969. Miller, Cl., Isard, S. Some perceptual consequences of linguistic rules. J. Verb. Learning Verb. Behav. , 1963,2, 217-228. Scholes, R. The role of grammaticality in the imitation of word strings by children and adults. J. Verb. Learning Verb. Behav., 1969, 8, 289-294. Thorndike, E. A teacher’s word book of the twenty thousand wordsfound mostfrequently and widely in general reading for children and young people. New York: Bureau of Publications, Teacher’s College, Columbia University, 1932. West, R., Ansbemy, M., Carr, A. The rehabilitation of speech. New York: Harper & Brothers, 1957. Wilcox, J., Tobin, H. Linguistic performance of hard-of-hearing and normal hearing children. J. Speech Hear. Res., 1974, 17, 286-293.
