Two-year-olds learn language quickly but how they exploit adult input remains obscure. Twenty-nine children aged 2;6 to 3;2, divided into three treatment groups, participated in an intervention experiment consisting of four sessions 1 week apart. Pre- and post-intervention sessions were identical for all children: children heard a wh-question and attempted to repeat it; a ‘talking bear’ answered. That same format was used for the two intervention sessions for children in a quasicontrol condition (Group QC). Children receiving modelling (Group M) heard a question twice before repeating it; those receiving implicit correction (Group IC) heard a question, attempted to repeat it, and heard it again. All groups improved in supplying and inverting an auxiliary for target questions with trained auxiliaries. Only experimental children generalized to auxiliaries on which they had not been trained. Very little input, if concentrated but varied, and presented so that the child attends to it and attempts to parse it, is sufficient for the rapid extraction and generalization of syntactic regularities. Children can learn even more efficiently than has been thought.

Observational and checklist measures of vocabulary composition have both recently been used to look at the absolute proportion of nouns in children's early vocabularies. However, they have tended to generate rather different results. The present study is an attempt to investigate the relationship between such measures in a sample of 26 children between 1;1 and 2;1 at approximately 50 and 100 words. The results show that although observational and checklist measures are significantly correlated, there are also systematic quantitative differences between them which seem to reflect a combination of checklist, maternal-report and observational sampling biases. This suggests that, although both kinds of measure may represent good indices of differences in vocabulary size and composition across children and hence be useful as dependent variables in correlational research, neither may be ideal for estimating the absolute proportion of nouns in children's vocabularies. The implication is that questions which rely on information about the absolute proportion of particular kinds of words in children's vocabularies can only be properly addressed by detailed longitudinal studies in which an attempt is made to collect more comprehensive vocabulary records for individual children.

Previous studies have suggested that paternal vocabulary selection in speech to young children may be more diverse or demanding than that of mothers. This study examined the speech of eight mothers and eight fathers to their young language learning children. Nominal usage was subjected to TTR and frequency-of-occurrence analyses. In general, while paternal speech does not appear to be more diverse than maternal speech, it does appear to be characterized by greater usage of rare vocabulary and significantly lower usage of common vocabulary than is maternal speech.

There are differences and similarities between Modern Standard Arabic (MSA) and spoken varieties of Arabic, in all language domains. To obtain preliminary insights into interactions between the acquisition of spoken and standard varieties of a language in a diglossic situation, we employed forced-choice grammaticality judgments to investigate morphosyntactic knowledge of MSA and the local variant of Palestinian Colloquial Arabic (PCA), in 60 Arabic-speaking children aged 6 ; 4 to 12 ; 4, from a school in Nazareth. We used morphosyntactic structures which either differed or were similar between PCA and standard Arabic. Children generally performed better on items presented in PCA than in standard Arabic, with the exception of constructions involving negation. Children performed better on items when the two constructions were similar in both language varieties. We discuss the results with respect to the multiple factors that affect acquisition in a diglossic situation, and relate our findings to the possibility of interference effects of diglossia on learning.

The late babbling productions of a French child are analysed and compared with a similar study of English-speaking children. English-speaking and French children are shown to share such universal phonetic preferences as cluster reduction, final devoicing, etc. However, there are also noticeable differences which may be ascribed to corresponding differences in the target language. Thus a selective, language-specific, phonetic acquisition has been taking place during the babbling stage. A comparison of the phonetic repertoires of French, English, Thai and the late babbling corpus confirmed the close similarity between the latter and French. This study reinforces the view that babbling is relevant to the study of linguistic performance.

This is an exploratory case study of the relation between speech output disturbances (dysfluencies) and the development of language production processes. The data consist of transcribed weekly speech samples of a Dutch boy between 2;4 and 2;11. The period of observation captures the early phase of the transition from ‘pre-grammatical’ to grammatical language. The frequency of occurrence of dysfluencies (i.e. repetitions, revisions and incomplete phrases) shows a significant increase and a subsequent decline. Whereas in the first half of the observation period the dysfluencies are distributed relatively randomly over sentences, in the second half they tend to concentrate in function words and sentence-initial words. The decline of dysfluency rate is shown to be related to an abundant use of a few ‘syntactic frames’. It is argued that these results reflect the emergence of a component in the speech production apparatus which is specifically dedicated to serial-order planning.

The positive effects of shared book reading on vocabulary and reading development are well attested (e.g., Bus, van Ijzendoorn, & Pellegrini, 1995). However, the role of shared book reading in grammatical development remains unclear. In this study, we conducted a construction-based analysis of caregivers’ child-directed speech during shared book reading and toy play and compared the grammatical profile of the child-directed speech generated during the two activities. The findings indicate that (a) the child-directed speech generated by shared book reading contains significantly more grammatically rich constructions than child-directed speech generated by toy play, and (b) the grammatical profile of the book itself affects the grammatical profile of the child-directed speech generated by shared book reading.

An American-Japanese comparison of maternal speech to 3-month-old infants is presented. Mother-infant dyads were videotaped in the laboratory, and the maternal speech was analysed by function and syntactic form. US mothers were more information-oriented than were Japanese mothers; they also used more question forms, especially yes/no questions. Japanese mothers were affect-oriented, and they used more nonsense, onomatopoeic sounds, baby talk, and babies' names. The differences between countries in maternal speech addressed to 3-month-olds appear to reflect characteristic culture-specific communicative styles as well as beliefs and values related to childrearing.

With the increase in interest in formulas, or apparently non-productive utterances in children's speech, a range of definitions has emerged and sometimes conflicting criteria have been proposed for their identification. These definitions of formulas are compared, and the criteria of Brown (1973), Wong Fillmore (1976), Peters (1983) and Plunkett (1990) for the recognition of formulas are reviewed. A preference rule System is proposed, which distinguishes necessary, typical and graded conditions for the recognition of formulas. Using these conditions, some of the formulas found in the data of one child acquiring Irish between 1;4 and 2;1 are examined. Issues such as length of units, frequency of occurrence and appropriateness of use are discussed. The methods developed in this study could be used to assess the importance of formulas in the language acquisition of other children.

The present study analysed formerly unexamined indirect routes for relationships between time 1 maternal speech and later child language development. Ten normally developing children in Brown's early stage 1 and their mothers were the subjects. For each dyad, two free-play sessions occurring five months apart were videotaped in the subjects' homes. Mothers' pragmatic language use was coded from time 1 sessions. Child language level was coded at both sessions. Even though time 1 scores of the outcome were controlled, seven of the ten relationships involving mother speech and child language development were indirectly related through one of two time 1 child language measures. The results indicate that a mother-driven, direct influence model may be inappropriate for many mother speech–child language development relationships. We argue that child-driven and mother-driven explanatory models for the indirect relationships are equally feasible.

The utterances of one French and one American infant at 0;5, 0;8, 0;11, and 1;2 were transcribed and acoustically analysed for syllable duration and vowel formant values. Both general and language-specific effects emerged in the longitudinal study. Initial similarities in the consonantal repertoires of both infants, increasing control in producing target F1 and F2 values, and developmental changes in babbling characteristics over time seem to reflect universal patterns. Yet the babbling of the infants differed in ways that appear to be due to differences in their language environments. Shifts in the infants' sound repertoires reflected phoneme frequencies in the adult languages. The English-learning infant produced more closed syllables, which is characteristic of English, than the French-learning infant. The French-learning infant tended to produce more regularly-timed nonfinal syllables and showed significantly more final-syllable lengthening (both characteristic of French) than the English-learning infant.

The aim of the present study was to analyze the relative influence of age at implantation, parental expansions, and child language internal factors on grammatical progress in children with cochlear implants (CI). Data analyses used two longitudinal corpora of spontaneous speech samples, one with twenty-two and one with twenty-six children, implanted between 0;6 and 3;10. Analyses were performed on the combined and separate samples. Regression analyses indicate that early child MLU is the strongest predictor of child MLU two and two-and-a-half years later, followed by parental expansions and age at implantation. Associations between earliest MLU gains and MLU two years later point to stability of individual differences. Early type and token frequencies of determiners predict MLU two years later more strongly than early frequency of lexical words. We conclude that features of CI children's very early language have considerable predictive value for later language outcomes.

The speech children spontaneously quote was examined in two studies. In Study 1, a corpus of personal narratives from 96 children aged 4;0 to 9;0 was analysed; Study 2 investigated reported speech in 25 younger children aged 1;2 to 5;2 interacting with their parents. In both studies, the frequency of reported speech increased with age. Direct quotation was more common than indirect or summarized quotation at all ages. In Study 1, children quoted themselves more frequently than any other speaker, and their mothers more frequently than their fathers. Directives were the most commonly reported speech act from the distant past in both older (Study 1) and younger (Study 2) children. In Study 1, girls used reported speech more frequently than did boys, and their quotations were more direct in form than were those of boys.

Lexical diffusion, as characterized by interword variation in production, was examined in phonological acquisition. The lexical variables of word frequency and neighbourhood density were hypothesized to facilitate sound change to varying degrees. Twelve children with functional phonological delays, aged 3;0 to 7;4, participated in an alternating treatments experiment to promote sound change. Independent variables were crossed to yield all logically possible combinations of high/low frequency and high/low density in treatment; the dependent measure was generalization accuracy in production. Results indicated word frequency was most facilitative in sound change, whereas, dense neighbourhood structure was least facilitative. The salience of frequency and avoidance of high density are discussed relative to the type of phonological change being induced in children's grammars, either phonetic or phonemic, and to the nature of children's representations. Results are further interpreted with reference to interactive models of language processing and optimality theoretic accounts of linguistic structure.

This study examined two- (n=10) and three-year-old (n=16) French–English bilingual children’s repairs of breakdowns in communication that occurred when they did not use the same language as their interlocutor (Language breakdowns) and for other reasons (e.g. inaudible utterance). The children played with an experimenter who used only one language (English or French) during the play session. Each time a child used the other language, the experimenter made up to five requests for clarification, from non-specific (What?) to specific (Can you say that in French/English?). The experimenter also made requests for clarification when breakdowns occurred for other reasons, e.g. the child spoke too softly, produced an ambiguous utterance, etc. Both the two- and three-year-olds were capable of repairing Language breakdowns by switching languages to match that of their experimenter and they avoided this repair strategy when attempting to repair Other breakdowns. Moreover, they switched languages in response to non-specific requests. The results indicate that even two-and-a-half-year-old bilingual children are capable of identifying their language choice as a cause of communication breakdowns and that they can differentiate Language from Other kinds of communication breakdowns.

The role of babbling in language development is not well understood. One source of evidence is the utterances of infants who were tracheostomized during the period in which they would normally have produced syllabic vocalization. We describe here the phonetic patterns and linguistic development of a girl called Jenny. She was tracheostomized and generally aphonic from 0;5–1;8 but cognitively and socially normal, with near-normal comprehension of language. Acoustic analyses of Jenny's utterances following decannulation revealed a tenth of the canonical syllables which might be expected in normally developing infants, an extremely small inventory of consonant-like segments, and a marked preference for labial obstruents. In these ways, she resembled a group of infants of the same age who also cannot hear their oral-motor movements, the congenitally deaf, suggesting that the audibility of babbling contributes to its onset. Two months following decannulation, when Jenny was 1;10, she produced only a handful of different words. We think this is because aphonia prevented her from discovering the referential value of vocal expression and discouraged the formation of a phonetic repertoire that could be appropriated for lexical service. This unusual case suggests that babbling normally facilitates the development of language and speech.

Data are presented which reflect a particular strategy used by a boy from 1; 10 to 2; 2 to manage certain polysyllabic words. Analysis shows that substitution – although probably an impetus for this strategy – was not involved in most or even all of the strategic processes themselves. An interpretation is made in terms of ‘underlying forms’ (Ingram 1970); details of the strategy and its component sub-strategies (‘ruses’) are presented.

In order to isolate the properties of language whose development can withstand wide variations in learning conditions, we have observed children who have not had access to any conventional linguistic input but who have otherwise experienced normal social environments. The children we study are deaf with hearing losses so severe that they cannot naturally acquire spoken language, and whose hearing parents have chosen not to expose them to a sign language. In previous work, we demonstrated that, despite their lack of conventional linguistic input, the children developed spontaneous gesture systems which were structured at the level of the sentence, with regularities identifiable across gestures in a sentence, akin to syntactic structure. The present study was undertaken to determine whether one of these deaf children's gesture systems was structured at a second level, the level of the gesture – that is, were there regularities within a gesture, akin to morphologic structure?

We have found that (1) the deaf child's gestures could be characterized by a paradigm of handshape and motion combinations which formed a matrix for virtually all of his spontaneous gestures, and (2) the deaf child's gesture system was considerably more complex than the model provided by his hearing mother. These data emphasize the child's contribution to structural regularity at the intra-word level, and suggest that such structure is a resilient property of language.

Williams syndrome (WS), a rare neurodevelopmental disorder, is of special interest to developmental psycholinguists because of its uneven linguistico-cognitive profile of abilities and deficits. One proficiency manifest in WS adolescents and adults is an unusually large vocabulary despite serious deficits in other domains. In this paper, rather than focus on vocabulary size, we explore the processes underlying vocabulary acquisition, i.e. how new words are learned. A WS group was compared to groups of normal MA-matched controls in the range 3–9 years in four different experiments testing for constraints on word learning. We show that in construing the meaning of new words, normal children at all ages display fast mapping and abide by the constraints tested: mutual exclusivity, whole object and taxonomic. By contrast, while the WS group showed fast mapping and the mutual exclusivity constraint, they did not abide by the whole object or taxonomic constraints. This suggests that measuring only the size of WS vocabulary can distort conclusions about the normalcy of WS language. Our study shows that despite equivalent behaviour (i.e. vocabulary test age), the processes underlying how vocabulary is acquired in WS follow a somewhat different path from that of normal children and that the atypically developing brain is not necessarily a window on normal development.