Infants' sensitivity to word units in fluent speech was examined by inserting 1 sec pauses either at boundaries between successive words (Coincident versions) or between syllables within words (Noncoincident versions). In Experiment 1, 24 11-month-olds listened significantly longer to the Coincident versions. In Experiment 2, 24 four-and-a-half-and 24 nine-month-olds did not exhibit the preference for the Coincident versions that the 11-month-olds showed. When the stimuli were low-pass filtered in Experiment 3, 24 11-month-olds showed no preference for the Coincident versions, suggesting they rely on more than prosodic cues. New stimulus materials in Experiment 4 indicated that responses by 24 11-month-olds to the Coincident and Noncoindent versions did not depend solely on prior familiarity with the targets. Two groups of 30 11-month-olds tested in Experiment 5 were as sensitive to boundaries for Strong/Weak words as for Weak/Strong words. Taken together, the results suggest that, by 11 months, infants are sensitive to word boundaries in fluent speech, and that this sensitivity depends on more than just prosodic information or prior knowledge of the words.

Intuitive syllabifications of 50 five- and six- and 50 eight-year-old children are studied in an experimental setting. The children syllabified Dutch disyllabic words with a single intervocalic consonant that were presented orally to them. The aim was to find out if these syllabifications adhered to the universal principles of syllable structure and if the children's syllabifications witnessed an overruling of the universal phonological constraints by language specific ones. Results indicate that universal principles are sufficient to explain syllabifications. Except for obligatory onset formation, other principles act as soft constraints that are influenced by factors such as stress and vowel and consonant quality. A language specific constraint proposed in the phonological literature, namely bimoraic minimality, is hypothesized to be a result of children's familiarization with the spelling conventions.

This longitudinal study was designed to examine the CDI-WORDS Short Form vocabulary checklist (Reznick & Goldsmith, 1989) as an index of language production. In particular, we were curious about: (1) the concurrent associations between the CDI-WORDS Short Form checklist measure and directly observed measures of lexical production; (2) the associations between Short Form checklists administered at different ages; and (3) the predictive associations between Short Form scores and subsequent measures of more general intellectual abilities (i.e. the Wechlser Preschool and Primary Scale of Intelligence; WPPSIR; Wechsler, 1989). In a sample of 32 children, significant correlations were found between CDI-WORDS Short Form scores and directly observed measures of lexical production at both 1;6 and 2;0. Further, both the Short Form checklist and the observed measure of lexical production were found to predict WPPSI-R Verbal IQ scores but not the Performance IQ scores at 4;0. Additional analyses demonstrated the predictive and convergent validity of the CDI-WORDS Short Form, and underscored the additional value of direct observational measures of lexical production during early lexical development.

The production of target consonant clusters at early stages of acquisition is analysed from a phonological representational perspective. The data stem from five normal monolingual German and four normal monolingual Spanish children at ages from 0;9 to 2;1, observed in naturalistic settings. At the beginning stages, target clusters are reduced to a single consonantal position, due to lack of branching of the syllabic constituents. This finding coincides with other results in the literature, which have in general been explained by means of universal principles. Nevertheless, there is an essential difference between the German and the Spanish data: German children tend to prefer the first consonant and Spanish children the second one. This difference can only be explained in terms of parameterization of syllabification, which in German takes place from left to right and in Spanish from right to left. At later stages, when clusters begin to be produced with two consonantal positions, they offer evidence for the beginning of branching of syllabic constituents, due to parameterization, and for the chronological order of the setting of the subsyllabic parameters. Our data offer evidence in favour of the following acquisitional hierarchy: CV > CVC > CVCC > CCVCC.

Research on categorization suggests that information conveyed by language may be a guide for children performing classification tasks. In our study we asked whether differences between languages in linguistic form influence this performance. Thirty-five three- and four-year-old monolingual speakers of Spanish and English, languages differing in the way they encode gender, were tested in their native countries on a classification task of familiar objects. This task assessed strategies used in (1) a free sort, (2) a sort with instructions to use natural gender, and (3) one (for the Spanish speakers) with specific instructions to use grammatical gender. Half of both the Spanish and the English groups used animacy as a sorting strategy in the first sort, whereas the majority of both groups sorted by natural gender in the second sort. Most Spanish speakers also used grammatical gender as a categorizing strategy in at least one of the sorts. Results suggest that both instructional context and language-specific experience can influence the ways children classify familiar referents.

Scholars have addressed a range of questions about language development, but for some reason have neglected to ask why infants begin to talk. Biologists often prefer ‘how’ to ‘why’ questions, but it is possible to ask about the immediate consequences of developing behaviours – an acceptable strategy for attacking causation – and psycholinguists can study the immediate consequences to the infant of behaviours that lead to linguistic competence. This process is demonstrated with a series of illustrative proposals as to the short- and long-term consequences of vocal learning and utterance storage, two developmental phases that lead to talking, as well as the act of talking itself. The goal is to encourage investigation of behavioural dispositions that nudge the child, by degrees, towards proficiency in the use of spoken language.

Several competing proposals for the (under)specification of phonological representations are evaluated against the facts of phonemic acquisition. Longitudinal evidence relating to the emergence of a voice contrast in the well-documented study of Amahl (from age 2;2 to 3;11) is reconsidered. Neither contrastive specification nor context-free radical underspecification is capable of accounting for the facts. The problem is in the characterization of the change in the status of a feature from being noncontrastive and conditioned by context at one stage to being contrastive with phonetic effects that diffuse gradually through the lexicon. Both frameworks must treat as accidental the persistence of the early substitution pattern and require the postulation of wholesale changes in underlying representations, where these changes do not accord well with the observed phonetic changes or with the facts available to the learner. Context-sensitive radical underspecification provides a plausible account of each stage and the transition between stages with minimal grammar change.

A longitudinal diary-and-videotape study of the production of phonological segments by a Spanish—English bilingual child, age 1;6–4;6, revealed a consistent separation of the phonological systems of the two languages from the earliest period, with minimal interference at later times. These results are in contrast to results obtained from another child in a similar study (Schnitzer & Krasinski, 1994). The relevance of these data to the issue of whether bilingual children first use a single system before acquiring two discrete languages is discussed, as is the general question of how to interpret the early phonological production of bilinguals.

Laryngeal-supralaryngeal cyclicity has been put forth as an acquisition principle that describes expansion of the phonemic inventory as a bivalent cycle with alternations between the elaboration of laryngeal and supralaryngeal properties of the system (Gierut, 1994). This study evaluated experimentally the claims of the principle by manipulating the domain of the cycle and the phase relationship of the cycle as independent variables, and by monitoring longitudinally the order of emergent phonemic distinctions in the sound systems of seven children with phonological delays (aged 3;4 to 5;8) as the dependent variable. Three general findings emerged: (1) the course of acquisition for all children was consistent with cyclicity; (2) there were no differences in phonemic acquisition between children taught a laryngeal as opposed to a supralaryngeal distinction; and (3) children taught out-of-phase with the cycle evidenced greater phonemic expansion than those taught inphase with the cycle.

Ten children at mean ages of o; 11.3 and o; 15.3 and their monolingual German-speaking mothers were audio- and videotaped in their homes while having a meal with a spoon (ordinary situation) and while feeding a doll with a spoon (play situation). Sentences spoken by the mothers that were comparable in length and sentence type across situations were analysed acoustically. In both data-collection sessions, it was found that the mothers spoke with the same mean amplitude in the two situations but they used higher mean fundamental frequency when speaking during the play situation than during the ordinary situation. In the first data-collection session, when the infants did not yet use meaningful words or engage in pretend play, the mothers also used a wider pitch range in the play situation than in the ordinary situation. It is concluded that mothers use both pitch height and pitch range to introduce the preverbal infant to the difference between non-play and play situations, and they continue to use variations in pitch height to mark the same distinction after the children have become active participants in pretend play activities. Implications of the results are discussed in terms of possible longitudinal patterns associated with mothers' use of intonational key and register.

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.

Maternal estensive naming was investigated in a cross-sectional study of 12 children aged 0;10, 1;3 and 1;6, and a follow-up study of four children aged 1;3. Display, demonstration and pointing were coded with regard to whether and how co-occurring speech referred to gesture focus. Multivariate log-linear frequency analyses found that mothers' coordination of speech with gesture varied with age and the gesture used. Maternal naming of objects was most frequent with children aged 0; 10. Maternal gesture-speech coordination with children aged 1;3 and 1;6 differed in two related ways: (1) actions were named more frequently than objects; and (2) mothers often combined gesture with complementary speech referring, not to gesture focus, but to an action to be performed with the object indicated. At all ages, pointing was rarely used to name ostensively, and occurred most often in combination with complementary reference. Maternal input was found to be significantly correlated with children's reported receptive vocabulary.

In order to separate competence and performance factors in acquisition of knowledge of syntactic subjects, we audiotaped and analysed the spontaneous speech of 20 Portuguese-speaking two-year-olds in natural conversation with Portuguese-speaking adults. We separated the children into three groups based on Mean Length of Utterance in Words: 1·5–1·99; 2·0–2·99; 3·0–4·99. Our cross-sectional data demonstrated that Portuguese-speaking children increased their use of subjects from 28% in the lowest-MLUW group to 57% in the highest-MLUW group. The children in the highest-MLUW group almost perfectly matched the adult speakers in the study on every measure. The increase in children's use of subjects was primarily due to an increase in the use of pronominal subjects. A comparison between Portuguese- and English-speaking children suggests that adult competence about the status of subjects is present at the onset of combinatorial speech, as shown by differential production of subjects. Each group also experiences performance limitations, as shown by the increase in subject use as development proceeds.

Passive structures are typically assumed to be one of the later acquired constructions in child language. English-speaking children have been shown to produce and comprehend their first simple passive structures productively by about age four and to master more complex structures by about age nine. Recent crosslinguistic data have shown that this pattern may not hold across languages of varying structures. This paper presents data from four Inuit children aged 2;0 to 3;6 that shows relatively early acquisition of both simple and complex forms of the passive. Within this age range children are productively producing truncated, full, action and experiential passives. Some possible reasons for this precociousness are explored including adult input and language structure.

This study examines children's uses of nominal determiners (‘local markings’) and utterance structure (‘global markings’) to introduce new referents. Two narratives were elicited from preschoolers, seven-year-olds, ten-year-olds, and adults in English (N = 80), French (N = 40), German (N = 40), and Chinese (N = 40). Given typological differences (e.g. richness of morphology), these languages rely differentially on local vs. global devices to mark newness: postverbal position is obligatory in Chinese (determiners optional), indefinite determiners in the other languages (position optional). Three findings recur across languages: obligatory newness markings emerge late (seven-year-olds); local markings emerge first, including Chinese optional ones; local and global markings are strongly related. Crosslinguistic differences also occur: English-speaking preschoolers use local markings least frequently; until adult age global markings are rare in English, not contrastive in German and not as frequent in Chinese as in French, despite obligatoriness. It is concluded that three factors determine acquisition: (1) universal discourse factors governing information flow; (2) cognitive factors resulting from the greater functional complexity of global markings; (3) language-specific factors related to how different systems map both grammatical and discourse functions onto forms.

The production of pointing and other gestures (e.g. reaching or indicative gestures) by 47 infants aged 1; 0 to 1; 6 was investigated in two experiments contrasting declarative-referential vs. imperative-instrumental conditions of communication. A further group of seven infants aged 0; 10 was examined in order to highlight pre-pointing transitional phenomena. Data analyses concerned gestures and associated vocalizations and visual checking with a social partner. Results show that gestures are produced differentially in the experimental conditions: while reaching is only produced in imperative-instrumental contexts, pointing is characteristic of declarative-referential contexts. The pattern of visual checking with the social partner also differentiates gestures; moreover, it shows developmental changes in the case of pointing. Results suggest that pointing relies on some awareness of ‘psychological’ processes (e.g. attention and sharing) in the other and the self, and that it is this which may account for the specific relevance of pointing for language development.

Prior empirical work in semantic development has produced an impressive finding showing that children can reliably detect a modal's relative force (e.g. that must is stronger sounding than may) by five-and-a-half years of age. We investigate the extent to which a representation of relative force can account for an understanding of epistemic modals when their logical meaning is considered (i.e. when modals are interpretable as expressions of necessary and possible conclusions). Experiment 1 presents a replication of Hirst & Weil's hidden-object task, which originally included the supremely forceful indicative is. Thirty-two five-year-olds were required to find a peanut hidden under one of two containers based on a pair of statements that contrasted is with has to, has to with might, or is with might. Half the children were entitled to search for the peanut upon hearing the two statements and half were required to indicate only where they would look. Results largely confirmed the influence of relative force in this paradigm. Both groups of children usually searched under the container associated with the stronger-sounding term. Experiment 2 employed a modified version of the hidden-object task in which contrasts presented one true and one false modal statement and 32 five-year-olds, 20 seven-year-olds, 16 nine-year-olds and 20 adults were asked to determine which of two statements was correct. Half the contrasts presented a relatively weaker-sounding modal term in the true statement and the other half presented equally forceful modal terms in the two statements. No age group systematically endorsed a false stronger-sounding modal statement over a true weaker-sounding one. The five-year-olds' rate of correct responding overall was above levels predicted by chance. Mature logical modal understanding was found among seven-year-olds who routinely endorsed a contrast's true modal statement. These findings suggest that deductive inference is an early semantic component of modal terms.

The influence of information level on the production accuracy of 20 children (22 to 28 months) was examined. The data were children's productions of nouns in sets of utterances referring to triplets of pictures representing noun-verb-noun utterances. In each triplet one noun remained the same, thus decreasing in information value from the first to the third picture (new, moderately old, and old information). Words representing new information were produced more accurately than words representing old information. The types of errors did not differ. Further evidence of this effect was provided by an examination of the duration of new versus old word productions by 12 of the children. Productions encoding new information were consistently longer on average than those encoding old information. The results provide experimental evidence of an effect observed in adults that indicates early sensitivity to information level. However, because of the children's young age, the effects are characterized as a speaker-internal process that only serendipitously corresponds to listener needs.