In two studies we use a pointing task to explore developmentally the nature of the knowledge that underlies three- and four-year-old children's ability to assign meaning to the intransitive structure. The results suggest that early in development children are sensitive to a first-noun-as-causal-agent cue and animacy cues when interpreting conjoined agent intransitives. The same children, however, do not appear to rely exclusively on the number of nouns as a cue to structure meaning. The pattern of results indicates that children are processing a number of cues when inferring the meaning of the conjoined agent intransitive. These cues appear to be in competition with each other and the cue that receives the most activation is used to infer the meaning of the construction. Critically, these studies suggest that children's knowledge of syntactic structures forms a network of organization, such that knowledge of one structure can impact on interpretation of other structures.

Although preschoolers are pervasively underinformative in their actual usage of verbal reference, a number of studies have shown that they nonetheless demonstrate sensitivity to listener informational needs, at least when environmental cues to this are obvious. We investigated two issues. The first concerned the types of visual cues to interlocutor informational needs which children aged 2;6 can process whilst producing complex referring expressions. The second was whether performance in experimental tasks related to naturalistic conversational proficiency. We found that 2;6-year-olds used fewer complex expressions when the objects were dissimilar compared to highly similar objects, indicating that they tailor their verbal expressions to the informational needs of another person, even when the cue to the informational need is relatively opaque. We also found a correlation between conversational skills as rated by the parents and the degree to which 2;6-year-olds could learn from feedback to produce complex referring expressions.

There is debate about how input variation influences child language. Most deaf children are exposed to a sign language from their non-fluent hearing parents and experience a delay in exposure to accessible language. A small number of children receive language input from their deaf parents who are fluent signers. Thus it is possible to document the impact of quality of input on early sign acquisition. The current study explores the outcomes of differential input in two groups of children aged two to five years: deaf children of hearing parents (DCHP) and deaf children of deaf parents (DCDP). Analysis of child sign language revealed DCDP had a more developed vocabulary and more phonological handshape types compared with DCHP. In naturalistic conversations deaf parents used more sign tokens and more phonological types than hearing parents. Results are discussed in terms of the effects of early input on subsequent language abilities.

This study investigates the role of acoustic salience and hearing impairment in learning phonologically minimal pairs. Picture-matching and object-matching tasks were used to investigate the learning of consonant and vowel minimal pairs in five- to six-year-old deaf children with a cochlear implant (CI), and children of the same age with normal hearing (NH). In both tasks, the CI children showed clear difficulties with learning minimal pairs. The NH children also showed some difficulties, however, particularly in the picture-matching task. Vowel minimal pairs were learned more successfully than consonant minimal pairs, particularly in the object-matching task. These results suggest that the ability to encode phonetic detail in novel words is not fully developed at age six and is affected by task demands and acoustic salience. CI children experience persistent difficulties with accurately mapping sound contrasts to novel meanings, but seem to benefit from the relative acoustic salience of vowel sounds.

This study investigates the emergence and development of the discourse-pragmatic functions of the Japanese subject markers wa and ga from a usage-based perspective (Tomasello, 2000). The use of each marker in longitudinal speech data for four Japanese children from 1;0 to 3;1 and their parents available in the CHILDES database (MacWhinney, 2000) was coded and analyzed. Findings showed that the four children initially used wa as a wh-question marker. They then gradually shifted its use to convey the proposition of given information. In contrast, the use of ga varied among the children. One child used ga with dynamic verbs in the past tense to report events he witnessed/experienced, while the other three children used it with a particular stative predicate in the present tense, expressing their subjective feeling toward referents. Findings were explained by the frequency of input to which the children had been exposed.

We report here on a series of elicited production experiments that investigate the production of indirect object and oblique relative clauses by monolingual child learners of English and Korean. Taken together, the results from the two languages point toward a pair of robust asymmetries: children manifest a preference for subject relative clauses over indirect object relative clauses, and for direct object relative clauses over oblique relative clauses. We consider various possible explanations for these preferences, of which the most promising seems to involve the requirement that the referent of the head noun be easily construed as what the relative clause is about.

This study examined accuracy in production and grammaticality judgements of verb morphology by eighteen Chinese-speaking children learning English as a second language (L2) followed longitudinally from four to six years of exposure to English, and who began to learn English at age 4;2. Children's growth in accuracy with verb morphology reached a plateau by six years, where 11/18 children did not display native-speaker levels of accuracy for one or more morphemes. Variation in children's accuracy with verb morphology was predicted by their English vocabulary size and verbal short-term memories primarily, and quality and quantity of English input at home secondarily. This study shows that even very young L2 learners might not all catch up to native speakers in this time frame and that non-age factors play a role in determining individual variation in child L2 learners’ long-term outcomes with English morphology.

This study investigates children's acquisition of the distinction between direct speech (Elephant said, “I get the football”) and indirect speech (Elephant said that he gets the football), by measuring children's interpretation of first, second, and third person pronouns. Based on evidence from various linguistic sources, we hypothesize that the direct–indirect distinction is acquired relatively late. We also predict more mistakes for third person pronouns compared to first and second person pronouns. We tested 136 Dutch-speaking children between four and twelve in a referent selection task and found that children interpret pronouns in direct speech predominantly as in indirect speech, supporting our hypothesis about a late acquisition of the direct–indirect distinction. In addition, we found differences between I, you, and he that deviate from a simple first and second vs. third person split. We discuss our results in the light of cross-linguistic findings of direct–indirect mixing.

Using a preferential looking paradigm, the current study examined the role that grammatical gender plays when preschool French-speaking toddlers process role nouns in the masculine form (e.g., chanteurs masculine ‘singers’). While being auditorily prompted with “Look at the ‘a role noun’!”, two- and three-year-olds were presented with two pictures of two characters (‘boy–boy’ versus ‘girl–boy’) with attributes of the given role noun (e.g., singers with microphone and music notes). All role nouns were presented in the masculine plural form, which, despite its use to refer to mixed-gender groups, can be interpreted as referring to men. We expected toddlers to be biased by stereotypes, yet when non-stereotypical role nouns were presented, toddlers were not influenced by grammatical gender, but by their own sex (even more so for three-year-old toddlers). The absence of sensitivity to grammatical cues for either age group is discussed in terms of the developmental awareness of grammatical gender.

The current study investigated school-aged children's internalization of the distributional patterns of English lexical stress as a function of vocabulary size. Sixty children (5;3 to 8;3) participated in the study. The children were asked to blend two individually presented, equally stressed syllables to produce disyllabic nonwords with different resulting structures in one of two frame sentences. The frame sentences were designed to elicit either a noun or verb interpretation of the nonword. Children's receptive vocabulary was also assessed. The results indicated that children more readily blended syllable pairs that resulted in trochaic-compatible word structures than in iambic-compatible structures. This effect was strongest in young children with large vocabularies. As for stress placement, all children were sensitive to the effect of word structure, but only children with the largest vocabularies were sensitive to the biasing effect of grammatical category (noun = trochee; verb = iamb). The study results are discussed with reference to the observation that speech motor skills develop in tandem with lexical acquisition and the hypothesis that phonological knowledge emerges in part from abstraction across lexical representations.

We designed a parent-directed home-visiting intervention targeting socioeconomic status (SES) disparities in children's early language environments. A randomized controlled trial was used to evaluate whether the intervention improved parents' knowledge of child language development and increased the amount and diversity of parent talk. Twenty-three mother–child dyads (12 experimental, 11 control, aged 1;5–3;0) participated in eight weekly hour-long home-visits. In the experimental group, but not the control group, parent knowledge of language development increased significantly one week and four months after the intervention. In lab-based observations, parent word types and tokens and child word types increased significantly one week, but not four months, post-intervention. In home-based observations, adult word tokens, conversational turn counts, and child vocalization counts increased significantly during the intervention, but not post-intervention. The results demonstrate the malleability of child-directed language behaviors and knowledge of child language development among low-SES parents.

In this study, age of onset (AoO) was investigated in five- and six-year-old bilingual Frisian–Dutch children. AoO to Dutch ranged between zero and four and had a positive effect on Dutch receptive vocabulary size, but hardly influenced the children's accurate use of Dutch inflection. The influence of AoO on vocabulary was more prominent than the influence of exposure. Regarding inflection, the reverse was found. Accuracy at using Frisian inflection emerged as a significant predictor; this transfer effect was modulated by lexical overlap between the two languages. This study shows that ‘the sooner the better’ does not necessarily hold for language development. In fact, for the correct use of inflection, it does not matter whether children start at age zero or four. For rapidly learning words in a new language it may be helpful to first build a substantial vocabulary in the first language before learning a new language.

We examined the effects of object attributes on children's descriptive patterns in a referential communication task. Thirty preschoolers described object pairs that were selected by the experimenter. The targets were defined by shared size or colour, and differed on the non-target dimension in half of the trials. The children also completed a non-verbal reasoning task with analogous stimuli. They selected objects after observing the experimenter make a choice and inferring the basis for selection. In the communication task, the children produced fewer size than colour descriptions, particularly when the size targets differed in colour. They also over-specified colour features more often than size. They did not show a similar challenge identifying size relationships in the non-verbal task. The results support the conclusion that target attributes have a systematic influence on children's referential performance. Potential mechanisms for these effects, and directions for future research are discussed.

Young children answer questions with longer delays than adults do, and they don't reach typical adult response times until several years later. We hypothesized that this prolonged pattern of delay in children's timing results from competing demands: to give an answer, children must understand a question while simultaneously planning and initiating their response. Even as children get older and more efficient in this process, the demands on them increase because their verbal responses become more complex. We analyzed conversational question–answer sequences between caregivers and their children from ages 1;8 to 3;5, finding that children (1) initiate simple answers more quickly than complex ones, (2) initiate simple answers quickly from an early age, and (3) initiate complex answers more quickly as they grow older. Our results suggest that children aim to respond quickly from the start, improving on earlier-acquired answer types while they begin to practice later-acquired, slower ones.

This study investigated how forty-six mothers modified their talk about familiar and unfamiliar nouns and verbs when interacting with their children with Down Syndrome (DS), language impairment (LI), or typical development (TD). Children (MLUs < 2·7) were group-matched on expressive vocabulary size. Mother–child dyads were recorded playing with toy animals (noun task) and action boxes (verb task). Mothers of children with DS used shorter utterances and more verb labels in salient positions than the other two groups. All mothers produced unfamiliar target nouns in short utterances, in utterance-final position, and with the referent perceptually available. Mothers also talked more about familiar nouns and verbs and labelled them more often and more consistently. These findings suggest that mothers of children in the early period of language development fine-tune their input in ways that reflect their children's vocabulary knowledge, but do so differently for nouns and verbs.

The number of unique words in children's speech is one of most basic statistics indicating their language development. We may, however, face difficulties when trying to accurately evaluate the number of unique words in a child's growing corpus over time with a limited sample size. This study proposes a novel technique to estimate the latent number of words from a series of words uttered by children. This technique utilizes statistical properties of the number of types as a function of the number of sampled tokens. We tested the practical effectiveness of the proposed method in the empirical data analysis of the cross-sectional and longitudinal samples. The converging empirical evidence indicates that the proposed estimator improves the accuracy of vocabulary size estimation over a set of existing estimators. Utilizing this efficient estimator, we propose a new sampling scheme for vocabulary assessment that has lower cost and higher accuracy compared to existing methods.

Before they are 3;0–3;6, children typically do not engage with peers in focused interaction, although they do with adults. With parents, children interact around the ‘here-and-now’. We hypothesize that young peers do not attempt to establish joint attention to present objects. Using the CHILDES database, we compared attention-directives produced by parents to children, children to peers, and children to parents. Of 391 English-speaking parents, 88% generated attention-directives, mostly Look!, See!, and Watch! Of 15 children (2;10–3;7) engaging in dyadic peer-interaction, only 26% produced such utterances. By comparison, 62% of 268 children (1;2–3;3) addressed such directives to parents. Interaction with peers in young children does not involve joint attention to a shared environmental focus, although it does with parents. The reason may be pragmatic: shared attention in parent–child dyads is a means to get information or help; it may seem pointless for a child to address such directives to a peer.

We tested German nine-month-olds’ reliance on pitch and metrical stress for segmentation. In a headturn-preference paradigm, infants were familiarized with trisyllabic words (weak–strong–weak (WSW) stress pattern) in sentence-contexts. The words were presented in one of three naturally occurring intonation conditions: one in which high pitch was aligned with the stressed syllable and two misalignment conditions (with high pitch preceding vs. following the stressed syllable). Infants were tested on the SW unit of the WSW carriers. Experiment 1 showed recognition only when the stressed syllable was high-pitched. Intonation of test items (similar vs. dissimilar to familiarization) had no influence (Experiment 2). Thus, German nine-month-olds perceive stressed syllables as word onsets only when high-pitched, although they already generalize over different pitch contours. Different mechanisms underlying this pattern of results are discussed.

This paper explores whether there is evidence for age and/or input effects in child L2 acquisition across three different linguistic domains, namely morphosyntax, vocabulary, and syntax–semantics. More specifically, it compares data from English-speaking children whose age of onset to L2 Dutch was between one and three years with data from children whose age of onset was between four and seven years in their acquisition of verb morphology, verb placement, vocabulary, and direct object scrambling. The main findings were that there were no significant differences between the two groups in any of these areas and, with the exception of scrambling, current amount of exposure was the only factor significantly related to children's scores. The paper discusses the theoretical significance of these findings with respect to the role of input in the language acquisition process and the claim that there is a critical period ending within (early) childhood.

Gestures and vocal elements interact from the early stages of language development, but the role of this interaction in the language learning process is not yet completely understood. The aim of this study is to explore gestural accompaniment's influence on the acoustic properties of vocalizations in the transition to first words. Eleven Spanish children aged 0;9 to 1;3 were observed longitudinally in a semi-structured play situation with an adult. Vocalizations were analyzed using several acoustic parameters based on those described by Oller et al. (2010). Results indicate that declarative vocalizations have fewer protosyllables than imperative ones, but only when they are produced with a gesture. Protosyllables duration and f(0) are more similar to those of mature speech when produced with pointing and declarative function than when produced with reaching gestures and imperative purposes. The proportion of canonical syllables produced increases with age, but only when combined with a gesture.