Two experiments are described which explore the relationship between parental reports of infants' receptive vocabularies at 1 ; 6 (Experiment 1a) or 1 ; 3, 1 ; 6 and 1 ; 9 (Experiment 1b) and the comprehension infants demonstrated in a preferential looking task. The instrument used was the Oxford CDI, a British English adaptation of the MacArthur-Bates CDI (Words & Gestures). Infants were shown pairs of images of familiar objects, either both name-known or both name-unknown according to their parent's responses on the CDI. At all ages, and on both name-known and name-unknown trials, preference for the target image increased significantly from baseline when infants heard the target's label. This discrepancy suggests that parental report underestimates infants' word knowledge.

Assessing whether domain-general mechanisms could account for language acquisition requires determining whether statistical regularities among surface cues in child directed speech (CDS) are sufficient for inducing deep syntactic and semantic structure. This paper reports a case study on the relation between pronoun usage in CDS, on the one hand, and broad verb classes, on the other. A corpus analysis reveals statistical regularities in co-occurrences between pronouns and verbs in CDS that could cue physical versus psychological verbs. A simulation demonstrates that a simple statistical learner can acquire these regularities and exploit them to activate verbs that are consistent with incomplete utterances in simple syntactic frames. Thus, in this case, surface regularities are sufficiently informative for inducing broad semantic categories. Children might use these regularities in pronoun/verb co-occurrences to help learn verbs, although whether they actually do so remains a topic of ongoing research.

Previous studies have suggested that intonation development in infants and toddlers reflects an interaction between physiological and linguistic influences. The immediate background research for this study, however, was based on vocalizations that were only one syllable in length. By extending the analysis to polysyllabic utterances, the present study evaluated a broader range of physiological constraints on intonation production than the maximally simple context of monosyllabic utterances had permitted. The width and direction of pitch change across one- and two-syllable nuclear tones were acoustically analyzed in utterances produced by 60 children between the ages of 0 ; 6 and 1 ; 11. The results showed that the children controlled the characteristic intonation pattern of English monosyllables by the age of 1 ; 6–1 ; 8. However, even the youngest groups of children produced relatively robust and adult-like intonation contours when the tone-bearing string was polysyllabic, suggesting that the trochaic or dactylic foot is the natural ‘unmarked’ unit of tone production. The asymmetrical results for one- versus two-syllable tones support the conclusion that width of pitch change largely reflects physiological universals in children's earliest vocalizations and language-specific learning after the age of 1 ; 6. Implications of the findings are also discussed in relation to the Trochaic Template Hypothesis. It is concluded that a bias for trochaic rhythms that some children demonstrate could be based, in part, on the child's sensitivity to physiological constraints on the velocity and range of intonational pitch change.

When two people talk about an object, they depend on joint attention, a prerequisite for setting up common ground in a conversational exchange. In this study, we analyze this process for parent and child, with data from 40 dyads, to show how adults initiate joint attention in talking to young children (mean ages 1 ; 6 and 3 ; 0). Adults first get their children's attention with a summons (e.g. Ready?, See this?), but cease using such forms once children give evidence of attending. Children signal their attention by looking at the target object, evidence used by the adults. Only at that point do adults begin to talk about the object. From then on, they use language and gesture to offer information about and maintain attention on the target. The techniques adults rely on are interactive: they establish joint attention and maintain it throughout the exchange.

The study evaluated whether durational and allophonic cues to word boundaries are intrinsic to syllable production, and so acquired with syllable structure, or whether they are suprasyllabic, and so acquired in phrasal contexts. Twenty preschool children (aged 3 ; 6 and 4 ; 6) produced: (1) single words with simple and complex onsets (e.g. nail vs. snail); and (2) two-word phrases with intervocalic consonant sequences and varying boundary locations (e.g. this nail vs. bitty snail). Comparisons between child and adult control productions showed that the durational juncture cue was emergent in the four-year-olds' productions of two-word phrases, but absent elsewhere. In contrast, the allophonic cue was evident even in the three-year-olds' productions of single words. Perceptual judgments showed that age- and type-dependent acoustic differences translated into differences in listener behavior. The differential acquisition of the two juncture cues is discussed with reference to the acquisition of articulatory timing control.

Parents' object labels can be distinguished by whether the child is already attending to the object (follow-in) or not (lead-in). Lead-in labels have been found to be associated with low vocabulary. The current study examines whether the relation between lead-in labels and child vocabulary is influenced by whether the child's attention is redirected. Eighteen mother–infant dyads were videotaped at 1 ; 2, 1 ; 6 and 1 ; 10. Results indicate that parents' use of successful lead-in labels is positively correlated with children's vocabulary, whereas use of unsuccessful labels is negatively correlated. Finally, use of gesture is associated with the redirective success of lead-in labels.

Previous research has examined children's ability to add inflections to nonsense words. The current experiments were designed to determine whether children, ranging in age from 1 ; 9 to 2 ; 10 (N=34), could demonstrate productivity by dropping verbal inflections. In Experiment 1, children added -ed and -ing to novel stems, and dropped them from novel inflected forms and did so largely appropriately. In Experiment 2, they dropped -ing from verbs, but not from nouns, suggesting that when young children drop inflections they tend to do so appropriately, and not simply for ease of pronunciation.

When presented with a pair of objects, one familiar and one unfamiliar, and asked to select the referent of a novel word, children reliably demonstrate the disambiguation effect and select the unfamiliar object. The current study investigated two competing word learning accounts of this effect: a pragmatic account and a word learning principles account. Two-, three- and four-year-olds were presented with four disambiguation conditions, a word/word, a word/fact, a fact/word and a fact/fact condition. A pragmatic account predicted disambiguation in all four conditions while a word learning principles account predicted disambiguation in the word/word and fact/word conditions. Results indicated that children disambiguated in word/word and fact/word conditions and two-year-olds disambiguated at above chance levels in the word/word condition but at below chance levels in the fact/fact condition. Because disambiguation varied both as a function of age and condition these findings are presented as challenges to a pragmatic account of the disambiguation effect.

The vocabulary development of 24 Italian children aged between 1 ; 4 and 1 ; 6 at the beginning of the study was longitudinally monitored on a monthly basis using the Italian version of the MacArthur Communicative Development Inventory drawn up by their mothers. This study analyzes data from children for whom two sampling stages were available; the first corresponding to a vocabulary size as close as possible to 200 words (mean 217, range 167–281), the second to a vocabulary size ranging from 400 to 650 words (mean 518, range 416–648). The children's vocabulary composition was analyzed by calculating, for each sampling stage, the percentage of common nouns, verbs and closed-class words. The increase in percentage points of the various lexical items between the first and second sampling stages was also analyzed. Data confirmed the predominance of nouns over verbs and closed-class words at both sampling stages, while verbs and closed-class words showed a higher percentage increase than nouns. The results provide evidence that children who reached the first sampling point at an earlier age had a higher percentage of nouns than children who reached the same stage at an older age. However, in the passage from the first to the second sampling point no relationship emerged between a style of acquisition based on the acquisition of nouns and an increase in the rate of vocabulary growth.