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.

The present study investigated the universality of the early development of young children's understanding and representation of false beliefs, and specifically, the effect of language on Chinese-speaking children's performance in false belief tasks under three between-subjects conditions. The three conditions differed only in the belief verb that was used in probe questions regarding one's own or another person's beliefs, namely the Chinese verbs, xiang, yiwei, and dang. While the three words are all appropriate to false beliefs, they have different connotations regarding the likelihood of a belief being false, with xiang being more neutral than either yiwei or dang. Experiment i involved thirty-five Chinese-speaking adults who responded to false belief tasks to be used in Experiment 2 in order both to establish an adult comparison and to obtain empirical evidence regarding how Chinese-speaking adults use the three belief verbs to describe different false belief situations. In Experiment 2, 188 three-, four-, and five-year-old Chinese-speaking children participated in three false belief tasks. They were asked to report about an individual's false belief when either xiang, yiwei, or dang was used in the probe question. Results revealed a rapid developmental pattern in Chinese-speaking children's understanding of false belief, which is similar to that found with Western children. In addition, children performed significantly better when yiwei and dang, which connote that the belief referred to may be false, were used in belief questions than when xiang, the more neutral verb, was used. This finding suggests an important role of language in assessing children's understanding of belief and false belief.

We investigated the effects of semantic predictability on children's preservation of the /t/-/d/ phonemic voice contrast in American English. In Experiment 1, a total of 36 seven-, nine-, and twelve-year-olds produced minimal pairs differing in intervocalic /t/ and /d/ in semantically biasing and semantically neutral passages. The seven-year-olds preserved the phonemic contrast in both passage types. However, for the nine- and twelve-year-olds, total word duration and preceding vowel duration preserved the /t/-/d/ contrast, but this interacted with semantic predictability. The contrast was preserved in the biasing and not in the neutral passages. The production results from the older children replicated previous findings from adults, demonstrating that semantic predictability influences speech production at both a lexical and a segmental level. In Experiment 2, listeners identified the tokens produced in Experiment 1. The identification results suggested that differences produced by speakers may not necessarily have a functional role for listeners. An interactive activation framework is proposed to account for the semantic effects on older children's and adults' production. For the youngest children, however, we suggest that pragmatic compensation and task demands interact with the effects of interactive activation.

Two experiments were conducted to examine infants' reliance on object shape versus colour for word generalization to animate and inanimate objects. A total of seventy-three infants aged 1;4 to 1;10 were taught labels for either novel vehicles or novel animals using a preferential looking procedure (Experiment 1) or an interactive procedure (Experiment 2). The results of both experiments indicated that infants limited their word generalization to those exemplars that shared shape similarity with the original referent for both animate and inanimate objects. These findings indicate that a strong reliance on shape is present earlier than previously shown. In Experiment 2, reliance on shape to generalize novel words did not vary as a function of vocabulary size. Thus reliance on shape versus colour for word generalization does not appear to increase in strength as a function of word learning during late infancy.

A suggestion exists in the child language literature that the meanings of natural kind terms are acquired before the meanings of colour terms. Explanations have typically claimed that object terms are more salient than property terms. Such explanations, however, tend to ignore the fact that natural kind terms refer to categories with sharp, clear boundaries while colour terms refer to categories with unclear or variable boundaries. Nonetheless, there has been little evidence to show that the delay in the acquisition of colour terms arises from these semantic properties. This study compares natural kind and colour naming (and corresponding comprehension) by 48 children, ranging in age from 3;0 to 5;5. The results suggest that, contra the salience view, the apparent delay in colour naming may be explained on solely semantic grounds.

Grammatical inflections such as the English plural noun -s and third person singular verb -s are acquired at different points in time by young children. This finding is typically attributed to factors such as relative semantic salience or the distinction between lexical and functional categories. In this study input frequency, sentence position, and duration were examined as possible contributing factors. In both conversations with and stories aimed at young children, noun plural inflections were found to be more frequent than third singular verb inflections, especially in sentence-final position. Analysis of the speech of four mothers reading stories to their two-year-old children confirmed that duration differences also exist in the input. Because fricatives were lengthened in sentence-final position and plural nouns were much more likely to appear in these positions than were third singular verb forms, plural nouns were significantly longer than third singular inflections on average. The possible implications of these findings for language learnability theories and accounts of grammatical deficits in specific language impairment are discussed.

Twenty economically disadvantaged preschoolers (mean age 3;7) were randomly assigned to an intervention or a control group, and their mothers' styles of eliciting narratives from their children were assessed before and after intervention. Mothers of intervention children were encouraged to spend more time in narrative conversation, ask more open-ended and context-eliciting questions, and encourage longer narratives through back-channel responses. Children's narrative and vocabulary skills were assessed before and after the year-long intervention and 14 children participated in a follow-up assessment a year later. Narrative measures included the number and length of narratives as well as how decontextualized and informative they were. Intervention children showed significant vocabulary improvement immediately after intervention terminated, and a year later they showed overall improvements in narrative skill. In particular, intervention children produced more context-setting descriptions about where and especially when the described events took place. Such decontextualized language has been emphasized as important for literacy acquisition.

Although most English-speaking children master the correct use of first and second person pronouns by three years, some children show persistent reversal errors in which they refer to themselves as you and to others as me. Recently, such differences have been attributed to the relative availability of overheard speech during the learning process. The present study tested this proposal with feed-forward neural networks learning these pronouns. Network learning speed and analysis of their knowledge representations confirmed the importance of exposure to shifting reference provided by overheard speech. Errorless pronoun learning was linked to the amount of overheard speech, interactions with a greater number of speakers, and prior knowledge of the basic-level kind PERSON.

Signed languages make unique demands on gaze during communication. Bilingual children acquiring both a spoken and a signed language must learn to differentiate gaze use for their two languages. Gaze during utterances was examined for a set of bilingual-bimodal twins acquiring spoken English and American Sign Language (ASL) and a set of monolingual twins acquiring ASL when the twins were aged 2;0, 3;0 and 4;0. The bilingual-bimodal twins differentiated their languages by age 3;0. Like the monolingual ASL twins, the bilingual-bimodal twins established mutual gaze at the beginning of their ASL utterances and either maintained gaze to the end or alternated gaze to include a terminal look. In contrast, like children acquiring spoken English monolingually, the bilingual-bimodal twins established mutual gaze infrequently for their spoken English utterances. When they did establish mutual gaze, it occurred later in their spoken utterances and they tended to look away before the end.

Recent studies indicate that young English-speaking children do not have a general understanding of the significance of SVO order in reversible sentences; that is, they seem to rely on verb-specific formulas (e.g. NPpusher – form of the verb PUSH – NPpushee) to interpret such sentences (Akhtar & Tomasello, 1997). This finding raises the possibility that young children may be open to learning non-SVO structures with novel transitive verbs. To test this hypothesis, 12 children in each of three age groups (two-year-olds, three-year-olds, and four-year-olds) were taught novel verbs, one in each of three sentence positions: medial (SVO), final (SOV), and initial (VSO). The younger age groups were equally likely to use the novel (non-English) orders spontaneously as to correct them to SVO order, whereas the oldest children consistently corrected these structures to SVO order. These results suggest that English-speaking children's acquisition of a truly general understanding of SVO order may be a gradual process involving generalization (learning) from examples. The findings are discussed in terms of recent data-driven learning accounts of grammar acquisition.

Cross-linguistic similarities and differences in early lexical and grammatical development are reported for 1001 English-speaking children and 386 Italian-speaking children between 1;6 and 2;6. Parents completed the English or Italian versions of the MacArthur Communicative Development Inventory: Words and Sentences, a parent report instrument that provides information about vocabulary size, vocabulary composition and grammatical complexity across this age range. The onset and subsequent growth of nouns, predicates, function words and social terms proved to be quite similar in both languages. No support was found for the prediction that verbs would emerge earlier in Italian, although Italians did produce a higher proportion of social terms, and there were small but intriguing differences in the shape of the growth curve for grammatical function words. A strikingly similar nonlinear relationship between grammatical complexity and vocabulary size was observed in both languages, and examination of the order in which function words are acquired also yielded more similarities than differences. However, a comparison of the longest sentences reported for a subset of children demonstrates large cross-linguistic differences in the amount of morphology that has been acquired in children matched for vocabulary size. Discussion revolves around the interplay between language-specific variations in the input to young children, and universal cognitive and social constraints on language development.

Icelandic and Norwegian past tense morphology contain strong patterns of inflection and two weak patterns of inflection. We report the results of an elicitation task that tests Icelandic and Norwegian children's knowledge of the past tense forms of a representative sample of verbs. This cross-sectional study of four-, six- and eight-year-old Icelandic (n=92) and Norwegian (n=96) children systematically manipulates verb characteristics such as type frequency, token frequency and phonological coherence – factors that are generally considered to have an important impact on the acquisition of inflectional morphology in other languages. Our findings confirm that these factors play an important role in the acquisition of Icelandic and Norwegian. In addition, the results indicate that the predominant source of errors in children shifts during the later stages of development from one weak verb class to the other. We conclude that these findings are consistent with the view that exemplar-based learning, whereby patterns of categorization and generalization are driven by similarity to known forms, appropriately characterizes the acquisition of inflectional systems by Icelandic and Norwegian children.

The first verbs to participate in VO and SVO combinations, and the temporal parameters of the spread of these combinatory patterns over different verbs were investigated. The longitudinal language observations of 16 children, one acquiring English, the others Hebrew, were examined. The children were observed once a week for 3–12 months, the observations starting when the children were still in the single-word stage (1;1–2;1) and ending when they were well into multiword speech (1;8–2;7). The results indicate that the more verbs children already know to combine in a certain pattern, the faster they learn new ones. Apparently children induce from individual word-combinations some general principles that facilitate further learning. The ‘pathbreaking verbs’ that begin the acquisition of a novel syntactic rule tend to be generic verbs expressing the relevant combinatorial property in a relatively pure fashion: the same verbs that children first combine with direct objects, are typical grammaticalized markers of transitivity in many languages. These verbs do not have HIGH TRANSITIVITY as defined by Hopper & Thompson (1980). Rather, they express fundamental ‘object relations’ of incorporation into, and ejection from the personal. Crosslinguistic evidence indicates that this may be the basic transitivity construct in languages. The results raise the possibility that lexical-specific learning of positional patterns is sufficient to account for the formation of syntactic abstractions.

It is well known that mothers give their infants lessons in conversational competence from an early age. This study considered how maternal gestures and prosody contribute to this developing competence. It examines how mothers use ostensive marking to point out common references at different stages of development. The corpus consisted of longitudinal observations of four mother–infant dyads during free play (infants aged 0;4 to 1;1), at three stages of sensorimotor development (III, IV and V). Four dimensions of ostensive marking were considered: (1) the span of the marked utterance (holistic vs. local); (2) the communication channel used (gestural vs. prosodic); (3) the type of gestural marker (oriented, iconic, conventional, beats); and (4) the type of prosodic marker (emphasis, prosodic cliché, reinforced nuclear stress, focal accent). Although there was no clear change in the patterns of specific types of gestural or prosodic markers, the results showed that mothers adapt their gestures to the infant's processing level. Between stages III and V, they move from holistic to local and from gestural to prosodic marking. Stage IV appears to be an excellent period for observing the transition.

This study examines the relationship between third person singular (3Psg) subject pronoun case and agreement, focusing on the hypothesis that these two grammatical subsystems develop together. This hypothesis is broken down into two separate, empirically testable hypotheses: (a) that correct subject case pronoun production and the production of agreement are correlated, and (b) that at the sentence level, correct case is dependent on the presence of agreement. Twenty-nine children between the ages of 2;6 and 4;0 were each audiotaped for approximately two hours playing and interacting with their primary caregivers. Transcribed production data showed that 3Psg masculine subject pronoun case was correlated with agreement marking, whereas 3Psg feminine subject pronoun case was not. This result suggests the influence of a retrieval factor, termed the DOUBLE-CELL EFFECT, on the her for she pronoun case error. At the utterance level, pronoun case was independent of the presence of agreement. Overall, the study indicates that the relationship between case and agreement may be discernible as a general correlation, yet indiscernible at the level of sentence production.

This study contributes to our understanding of sociocultural variation in children's early storytelling by comparing co-narrations produced by children and their families from two European-American communities, one working-class and one middle-class. Six children from each community were observed in their homes at 2;6 and 3;0 years of age, yielding a corpus of nearly 400 naturally-occurring co-narrations of past experience. Analyses of generic properties, content, and emotion talk revealed a complex configuration of similarities and differences. Working-class and middle-class families produced co-narrations that were similar in referential/evaluative functions and temporal structure, with a preponderance of positive content. Working-class families produced twice as many co-narrations as their middle-class counterparts, produced more negative emotion talk, and used more dramatic language for conveying negative emotional experience. These findings suggest that (1) differentiation between working-class and middle-class communities in the content of early narratives may occur primarily with respect to negative experience and (2) researchers need to go beyond emotion state terms in order to accurately represent sociocultural variation in personal storytelling.

Despite previous work showing that mothers, fathers, and siblings provide negative evidence regarding children's grammatical errors, the role of linguistic input remains controversial. Since most work in this area has concentrated on negative evidence in the mother–child dyad, this study extended prior work by comparing mothers', fathers' and siblings' corrective repetitions to children's errors across different family settings. Fourteen children (2;3) were videotaped interacting with their mothers, fathers, and siblings (4;1) in dyad, triad, and tetrad settings. Analyses revealed that mothers and fathers provided more corrective repetitions than siblings did. Although the size of the setting did not differentiate responding, when specific configurations were examined differences emerged. Analyses of individual families revealed that all children received feedback following syntax errors. These results are discussed in terms of current negative evidence research.

Blind children are considered to use personal reference terms late and with a great deal of reversal errors. However, in previous research, there has been a dearth of both quantitative and qualitative data on their use of pronouns. In the present paper data from a longitudinal study of five children (three totally blind, one partially sighted, and one sighted) is presented. The children had different ages at the begining of the study, ranging from 0;9 to 2;5, and were followed for a time span of over 12 months. Every spatial deictic term and personal reference term used by the children was analysed. Special attention was given to the analysis of the reversal errors. The data obtained clearly showed that the blind children began to use personal reference terms as early as the sighted children, and that the use of reversals was not a general characteristic of the language of the blind children, since only one of the four blind or partially sighted children produced a noticeable percentage of reversals. The analysis of the contexts in which reversal errors were produced showed that imitation does not fully explain them, and some proposals for a multiplex explanation of reversals are offered. Thus, the data do not give support to the idea that blind children in general show problems with pronouns, nor to those claims that link blind children with autistic children in this regard.

In order to begin to learn a language, young children must be able to locate and distinguish linguistic units in the speech they hear. A number of cues in the speech stream may aid them in this task. Some cues, such as frequently occurring grammatical morphemes and prosodic changes at linguistic boundaries are inherent in the language. Other cues, such as short utterance length and placement of key words in utterance-final position, are not integral to the grammar of the language but are characteristically provided by caregivers. Although previous studies suggest that even infants are sensitive to many of these cues, it is not clear that young listeners actually use them in assigning structure to sentences. The experiments reported here asked whether 60 children aged 2;0 to 2;2 used grammatical and caregiver cues in sentence comprehension and how different types of cues interacted. Two findings are of note: children used all of the cues tested, and the presence of one type of cue did not diminish use of another.

Processes by which children interpret homonyms were examined. Participants were 16 two- and three-year-olds, 32 four-year-olds, 32 seven-year-olds and 32 ten-year-olds. Each child individually was asked to interpret keywords from stories read aloud by an examiner. Keywords were homonyms, nonsense words, or unambiguous words. For the three older groups, response times (RTs) to unambiguous words were significantly shorter than RTs to homonyms and nonsense words, when interpretations for all three-word types were consistent with the story contexts. Seven-year-olds had longer RTs for homonyms versus nonsense words. RTs did not vary among responses to homonyms. Four- and seven-year-olds had longer RTs for inappropriate, versus appropriate, nonsense-word interpretations. The number of cues recalled from a story about a keyword did not differ across appropriately versus inappropriately interpreted homonyms, but did differ across appropriately versus inappropriately interpreted nonsense words. These findings have implications for understanding how children arrive at literal interpretations of homonyms.