One problem of interest in child language study has been specifying what features of the speech situation determine what children will say. Several cognitively based approaches to child language development have proposed principles of ‘informativeness’ to explain the child's choice of word(s). These principles predict that the child will choose the ‘most informative’ element of a situation and encode it in speech. Detailed inspection of this view reveals that the notion of ‘informativeness’ is not rigorously denned as in information theory, and would require the development of formal semantic and pragmatic information theories. Simpler accounts of available data do not require the notion of ‘information’.

Discrimination of synthetically produced stimuli differing along the voice onset time continuum was assessed for infants and adults within the context of the Visually Reinforced Infant Speech Discrimination (VRISD) paradigm. English-learning infants' discrimination abilities were compared with two groups of English-speaking adults (a phonetically naive and a phonetically sophisticated group). Contrary to the predictions of the innateness hypothesis, English-learning infants showed evidence of discrimination only across the English phoneme boundary. Adults, on the other hand, were very successful in discriminating both across and within a range of phoneme boundaries. These results are discussed in terms of the presumed relationship between categorical perception and linguistic processing and in terms of synthetic speech continua.

Lists of the first 50 words comprehended and produced by eight infants between 0; 9 and 1; 8 were compared. Comprehension development began earlier (around 0; 9) and reached the 50-word level (age 1; 1) earlier than production development (ages 1; 0 and 1; 6 respectively) and rate of word acquisition for comprehension was twice that of production, confirming the hypothesis that comprehension precedes production for lexical development. Word-class analysis revealed differences in the proportion and type of action words in comprehension and production vocabularies. It is suggested that action is central to lexical development but is expressed differently in comprehension, where action words are used to initiate actions, and production, where non-action words accompany the child's actions.

The attribution of function of various kinds to elements of child speech is discussed, and the question of the validity of the interpretations on which such attribution rests is explored with reference to Halliday's work on the development of meaning. Work in the philosophy of language is used to explore the kind of evidence needed for valid interpretation, and its systematic nature within a framework of the structure of linguistic behaviour. It is argued that theoretical clarity in this area would aid the study of both language use and language acquisition.

A number of phonologists have observed the frequent occurrence of ‘devoiced’ obstruents in word-final position in children's utterances. Although such transcription-based accounts have provided evidence of the phenomenon, physical phonetic properties of devoiced consonants have not been described. Therefore, characteristics of voicing control for ‘voiced’ and ‘voiceless’ stops produced by five English-speaking children aged 2; 6–3; 0, five aged 4; 0–4; 6, and five adults were investigated in terms of (1) the percentage of all stop productions evidencing ‘devoicing’ during consonant closure, and (2) in the case of devoiced stops, the proportion of consonant closure evidencing voicing. Both groups of children revealed substantial amounts of consonantal devoicing when compared with the adults; in addition, the proportion of stop closure evidencing voicing was considerably less for the children than for the adults. It was also observed, however, that the children's ‘devoiced’ stops revealed significantly more voicing than their phonemically ‘voiceless’ stop productions.

Two suprasegmental characteristics of three children's single-word, successive single-word and multiple-word utterances were examined spectrographically. The location of terminal pitch contour and the duration of words were compared across the three utterance types. It was found that successive single-word utterances shared suprasegmental patterns, on these dimensions, with multiple-word forms but not with single words. It is argued that successive single-word utterances are not simply single words uttered in close temporal proximity. Further, an account of the underlying organization of successive utterances is proposed.

The behaviour of 32 mothers during an object-retrieval game was analysed in terms of the hints and ‘clues’ they used to direct their children's attention. Age-related differences were found in the type of information offered; the prompts 2; 0-year-olds received primarily concerned the target-objects' whereabouts, whereas 2; 6-year-olds' mothers referred to the target-objects (especially those unfamiliar by name) in terms of the children's background knowledge of the objects' functions or associations, as well. Possible explanations for these changes are discussed and the view is advanced that these differences should be interpreted as reflecting changes in the way mothers structure the task for their children as they become more independent problem-solvers.

Both longitudinal and experimental evidence were used in an examination of the development of adjectives vs. inflections for the expression of size and value concepts in Italian children. The longitudinal speech production records for two Italian children suggest that the concepts of size and value are understood and expressed linguistically by 2 years. One child acquired both adjectival and inflectional expressions for size simultaneously, while the other used adjectives for size and value several months prior to the acquisition of corresponding inflections. However, both children demonstrated productive use of size inflections at around MLU 3·0. A subsequent experiment with 84 children, ranging from 2 to 6 years, suggests that comprehension of size and value inflections is restricted to a narrow, denotative set of meanings based predominately on a strict interpretation in terms of size. This pattern stands in marked contrast to adult patterns on the same experiment, in which size inflections are interpreted connotatively as well, with meanings based on positive and negative affect as well as size. The relative contribution of Connotative vs. denotative factors in the development of reference is discussed.

This study investigated the relationships between children's linguistic environments and their language acquisition. Speech samples taken from seven firstborn children and their mothers when the children were 1; 6 and 2; 3 were analysed within a number of semantic and syntactic categories to determine correlations between mothers' speech and subsequent language development. Several characteristics of mothers' speech (e.g. utterance length, use of pronouns) significantly predicted later child speech. The significant correlations suggested that mothers' choice of simple constructions facilitated language growth. Further, they showed that the motherese code differed from adult-adult speech in ways which aided language development. Differences between our study and previous investigations of environmental effects on language development probably resulted from the failure of earlier investigations to take into account children's level of language competence at the time when environmental effects were assessed.

This study investigates the surface forms which mothers use to direct their children's behaviour. It is generally supposed that social factors control a speaker's choice of directive form. However, it is shown that mothers' use of the various forms may be related to a cognitive variable, viz. the degree to which the forms possess the surface properties and, hence, clarity of canonical imperatives. As children get older, mothers' directives lose, in a meaningful order, properties which help to specify their mood and content. It is suggested that the social properties of the context do eventually replace the cognitive demands of the various forms as the primary influence on mother's choices.

Longitudinal data on the development of personal inflections in Portuguese are presented. Analysis of the data reveals that, initially, the subjects used a single inflection for all verbs, regardless of the intended subject. The first formal distinction to appear was between verbs bearing the unmarked ending and those inflected for first person singular. Analyses of the acquisition of the standard first person inflections are presented in the form of rules; overgeneralization of these rules is evident, especially in perfect tense verbs. Possible explanations for the use of the third person singular verb form as the unmarked form are discussed.

Judgements about the acceptability of anomalous and non-anomalous sentences were elicited from children between the ages of 2; 0 and 5; 0. Generally such judgements have been assumed to be a direct reflection of linguistic competence. Longitudinal study of individual children indicated that developmental changes in children's judgemental capacities were erratic, with sudden regressions in performance as well as sudden improvements. This was especially true of the youngest children, aged between 2; 0 and 3; 6. It appeared that, despite irregularity, certain general developmental patterns could be discerned. It is difficult to reconcile these findings with a view of sentence judgements which assumes that they directly represent linguistic competence. It is suggested that the most satisfactory explanation of the developmental data must rest on the assumption that not simply linguistic factors, but also cognitive/experiential factors are involved in sentence judgements.

Twelve nursery school children (mean age = 3; 9) attempted to imitate sentences which varied systematically in rate of presentation, intonation and length. The children more successfully imitated shorter sentences than longer ones, and sentences spoken at a rate nearer their own than sentences spoken at slower or faster rates. The imitation of long sentences read with normal intonation was superior to the imitation of long sentences read with flat intonation. Since adults frequently address children in short sentences, spoken slowly and with exaggerated intonation, these results indicate that these speech modifications may enhance the children's language comprehension.

This study challenges the semantic relations categories widely used for explaining children's early utterances. Ten 3-year-olds were asked two sets of questions involving the verb + with construction. Their responses were categorized according to existing semantic relations categories such as instrumental and locative. Problems with this approach emerged which were solved by developing a more simple dichotomous category system. The children responded by naming an item which is characteristically present for the duration of the given verb and not beyond its duration (chew with food). Thus the chosen item's presence was BOUNDED by the duration of the activity. When several items fitted the bounded criterion, the one most necessary for carrying out the activity was selected, and when no items fitted the bounded criterion, a non-bounded or continuously present item was reluctantly chosen.

Comprehension of words like here and there demands an ability to take the speaker as reference point whether or not his position agrees with one's own. Because children are known to have difficulty taking another person's viewpoint into account, it was hypothesized that children would be able to understand here and there with the speaker as reference point only after they were able to understand the terms with self as reference point. Fifty children age 2;6–3;6 were presented with two toys spaced a few feet apart and asked ‘Which one is over here/there?’ There were three conditions: E and S both sat next to (1) the same toy; (2) a different toy; and (3) E sat next to one toy while the other toy was near no-one. Contrary to the hypothesis, it was found that children did not comprehend the words with self as reference point first. Instead, the words appear to be understood first I with respect to an inconsistent reference point before children learn that the reference point is always the speaker.

Young children described objects which differed on three simultaneous dimensions, using adjective combinations appropriate to the dimensions. Three- and 6-year-olds displayed significant ordering preferences for these adjectives, which agreed with the ordering preferences of adults in the same task. Four- and 5-year-olds were less constrained in their adjective ordering, although descriptive competence with the adjectives improved greatly at age five. In a comprehension task, the children located the objects from verbal descriptions which used the same adjectives. Neither latency nor accuracy of comprehension was affected by the order of adjectives in the description at any age. The children also reproduced the adjectives in different orders; the few errors which occurred were unrelated to adjective order.

The interrelation of semantic and communicative factors was considered in three children's single-word responses to adult questions. Parents asked more yes/no than naming questions. Children were able to use yes and no appropriately, but did not always do so. The children seemed to have related the form of yes/no questions to the use of yes/no answers, but communicatively were not always willing or able to produce yes/no answers when required. Naming questions were more often followed by appropriate than by inappropriate utterances. The relation of these findings to the importance of naming in early language acquisition, and to the findings of Horgan (1977) and Steffensen (1977) was considered.

Criteria were devised to distinguish between literal and metaphoric word usage in early language. These criteria were applied to the spontaneous speech transcripts of one child between 2; 3 and 4; 10.15. All unconventional word uses were identified and were then scored as overextensions, anomalies, or metaphors. The majority of unconventional word uses proved to be metaphors. Moreover, a developmental sequence of types of metaphors produced was found: those metaphors predominant during year 2 were based on the pretend actions of symbolic play; those predominant at year 4 were based on perceptual grounds alone, without the support of action.

It is argued in this paper that 4-year-old children do not perform logical operations corresponding to formal logic upon the sentential components of implicative verbs to produce the indirect implications, as was suggested by Macnamara, Baker & Olson (1976). First, it is shown that the indirect implications tested by Macnamara et al. are not the implications which would be derived on the basis of formal reasoning. Second, additional empirical evidence is presented to show that when children hear a story containing a sentence with an implicative verb they do not combine the sentential components of that implicative verb (i.e. the presuppositions and implicative) to arrive at the implication of their conjunction. It is argued that the children draw upon their past personal knowledge concerning the event described in the story and import additional premises where necessary in order to derive the indirect implications.

Comprehension of event order was compared for reversible ‘X because Y’ (‘Y because X’ is also logical) and non-reversible ‘X because Y’ sentences. Children aged 5; 8–10; 11 chose one of two picture sequences, differing in event order, and put two pictures in first/last order to match a sentence ‘X because Y’ (order of mention violates temporal order) or ‘Because Y, X’ (order of mention preserves temporal order). Reversibility and clause order effects reflected the use of semantic probability cues and order-of-mention strategies for comprehension. Judgements were also made of grammatical acceptability for correct and reversed ‘X because Y’ sentences. Response strategies used in the two experiments suggest that development of comprehension of the role of because reflects acquired independence from contextual support and acquisition of a meaning component: ORDER.