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.

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.

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.

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.

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.

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.

The aim of this study is to determine universal vs. language-specific aspects of children's ability to organize cohesive anaphoric relations in discourse. Analyses examine narratives produced on the basis of two picture sequences by subjects of four ages (preschoolers, seven-year-olds, ten-year-olds, adults) in four languages: English (n = 80), German (n = 40), French (n = 40), and Mandarin Chinese (n = 40). Particular attention is placed on the impact of syntactic, semantic, and pragmatic factors in determining the uses of referring expressions and of word order in the maintenance of reference to the animate characters. Although subjecthood and agency determine NP position within the clause, role relations in discourse coreference account for NP form in all languages, notwithstanding some variations across languages, ages, and referents (e.g. density of coreference, null elements vs. overt pronouns, clause structures). It is concluded that the development of anaphora is determined by universal pragmatic principles and by language-specific properties characterizing how languages map discourse-internal and sentence-internal functions onto the same forms.

Six children were studied from the age of 0;6 to 1;6 in order to chart their developing comprehension vocabularies from the first to the 100th word. Observational data were used in the first instance to identify newly comprehended words and then controlled testing was carried out for each word to confirm and expand the observational data. Comprehension of words was divided into four categories – object names, context-bound object words, action words and personal names. The relative frequency of the different categories of word was found to change with the size of the comprehension vocabulary as personal names decreased in importance and both object names and action words became increasingly more common. There was considerable variation among the six children especially in the proportion of object names and action words that they understood but vocabulary composition became highly stable between 60 and 100 words.

In this case study we investigate how early a developing bilingual exposed simultaneously to English and Spanish can make appropriate language choices. We propose two methodological requirements for studies of this kind: (1) detailed records of the development of the child's lexicon; and (2) data collection in more than one language context. Our own study relies on detailed records of the child's cumulative vocabulary from the first word at ten months, and on weekly audiovideo recordings in both English and Spanish contexts from age 1;3. Analysis of the data shows a strong tendency for the language of the child's utterances to match that of the context at ages 1;7–1;8.

APPARENT CONTRADICTIONS, e.g. Did Susan like her supper? – Yes and no, involve asserting and denying the same proposition. They therefore violate the classical LAW OF NON-CONTRADICTION, suggesting the use of non-classical INTERPRETIVE STRUCTURES in natural language and reasoning. Experiment 1 explores the range of such interpretive structures available to adults (n = 24) in their reasoning about an apparent contradiction. Experiment 2 uses a similar task to study the emergence of these interpretive structures in young children's reasoning (3;6 to 8;4, n = 48). Results suggest an early facility with resolution strategies relating to OBJECT STRUCTURE (as in, Maybe Susan liked one part of supper but didn't like another part) and an initial tendency to focus on the negative by referring to it first (as in, Maybe Susan didn't like one part of supper but did like another part). We discuss the results in terms of the NATURAL LOGIC of objects and their properties, and the LOGICAL RESOURCES available to young children.