This paper investigates six- to nine-year-old children's acquisition of evidentiality. In two minimally different tasks we assess whether children can be made to use a particular source of information by presenting them with a specific evidential term. That is, we assess whether children have an explicit awareness of the source requirement of the evidential terms. The results demonstrate that children explicitly understand the direct evidential term, but not the indirect evidential terms. Interestingly, the direct evidential term tested (Dutch lijken) does not encode high speaker certainty. Hence, even though the child cannot rely on speaker certainty to provide an answer, the results still show that direct evidentiality is acquired before indirect evidentiality.

This longitudinal study involving 101 Dutch four- and five-year-olds charts indirect request (IR) and mental state term (MST) understanding and investigates the role that Theory of Mind (ToM) and general linguistic ability (vocabulary, syntax, and spatial language) play in this development. The results showed basic understanding of IR and MST in four-year-olds, but full understanding had not been reached even at five years old. Furthermore, although ToM predicted both IR and MST when linguistic ability was not taken into account, this relationship was no longer significant once the language measures were added. Linguistic ability thus seems to play an important role in the development of both IR and MST. Additional analyses revealed that whereas syntactic ability was the primary predictor of IR, spatial language was the best predictor of MST, suggesting that IR relies primarily on general linguistic skills, but that more specific aspects of language may bootstrap MST.

This paper examines the production of word-initial stops by two simultaneous trilingual sisters, aged 6;8 and 8;1, who receive regular input in Italian and English from multiple speakers, but in Spanish from only one person. The children's productions in each language were analyzed acoustically and compared to those of their main input providers. The results revealed consistent cross-linguistic differences by both children, including between Italian and Spanish stops, although these have identical properties in the speech of Italian- and Spanish-speaking adults. While the children's English stops were largely target-like, their Italian stops exhibited non-target-like realizations in the direction of English, suggesting interactions. Interestingly, their Spanish productions were largely unaffected by cross-linguistic interactions, with target-like voiceless stops, and voiced stops predominantly realized as spirants. These findings raise interesting questions about phonological development in multilingual settings and demonstrate that the number and type of input providers may crucially affect cross-linguistic interactions.

There is a noted advantage of dense neighborhoods in language acquisition, but the learning mechanism that drives the effect is not well understood. Two hypotheses – long-term auditory word priming and phonological working memory – have been advanced in the literature as viable accounts. These were evaluated in two treatment studies enrolling twelve children with phonological delay. Study 1 exposed children to dense neighbors versus non-neighbors before training sound production in evaluation of the priming hypothesis. Study 2 exposed children to the same stimuli after training sound production as a test of the phonological working memory hypothesis. Results showed that neighbors led to greater phonological generalization than non-neighbors, but only when presented prior to training production. There was little generalization and no differential effect of exposure to neighbors or non-neighbors after training production. Priming was thus supported as a possible mechanism of learning behind the dense neighborhood advantage in phonological acquisition.

We examined code-switching (CS) in the speech of twenty-four bilingual caregivers when speaking with their 18- to 24-month-old children. All parents CS at least once in a short play session, and some code-switched quite often (over 1/3 of utterances). This CS included both inter-sentential and intra-sentential switches, suggesting that at least some children are frequently exposed to mixed-language sentences. However, we found no evidence that this exposure to CS had any detrimental effect on children's word learning: children's overall vocabulary size did not relate to parental inter-sentential CS behavior, and was positively related to within-sentence CS. Parents often repeated words across their two languages, but this did not appear to increase the likelihood of children having translation equivalents in their vocabulary. In short, parents appear to CS fairly often to young children, even within sentences, but there is no evidence that this delays child lexical acquisition.

The ‘Production Effect’ (PE) refers to a memory advantage for items studied aloud over items studied silently. Thus, vocalizing may serve as a mnemonic that can be used to assist learners in improving their memory for new concepts. Although many other types of mnemonic have been suggested in the literature, the PE seems especially appropriate for young children, as it does not involve literacy skills. The present study is a first investigation of the PE in children. In two experiments we tested five-year-olds in a PE paradigm using pictures of objects as stimuli. In Experiment 1, pictures of familiar objects were presented to be remembered, and in Experiment 2 we used pictures of unfamiliar objects (evaluating new vocabulary acquisition). In both experiments we showed a memory advantage for vocally produced words (‘look and say’) over other types of learning (‘look’, ‘look and listen’), suggesting the PE as a prominent memory and learning tool.

This longitudinal case study documents the emergence of bilingualism in a young monolingual Mandarin boy on the basis of an acoustic analysis of his vowel productions recorded via a picture-naming task over 20 months following his enrollment in an all-English (L2) preschool at the age of 3;7. The study examined (1) his initial L2 vowel space, (2) the process of L1-L2 separation, and (3) his L1 vowel system in relation to L2. The child initially utilized his L1 base in building the L2 vowel system. The L1-L2 separation started from a drastic restructuring of his working vowel space to create maximal contrast between the two languages. Meanwhile, L1 developmental processes and influence of L2 on L1 were also in effect. The developmental profile of this child uncovered strategies sequential bilingual children may use to restructure their phonetic space and construct a new system of contrasts in L2.

We investigated whether children at the ages of two and three years understand that a speaker's use of the definite article specifies a referent that is in common ground between speaker and listener. An experimenter and a child engaged in joint actions in which the experimenter chose one of three similar objects of the same category to perform an action. In subsequent interactions children were asked to get ‘the X’ or ‘a X’. When children were instructed with the definite article they chose the shared object significantly more often than when they were instructed with the indefinite article in which case children's choice was at chance. The findings show that in their third year children use shared experiences to interpret the speaker's communicative intention underlying her referential choice. The results are discussed with respect to children's representation of linguistic categories and the role of joint action for establishing common ground.

This study compares parental pause and utterance duration in conversations with Swedish speaking children at age 1;6 who have either a large, typical, or small expressive vocabulary, as measured by the Swedish version of the McArthur-Bates CDI. The adjustments that parents do when they speak to children are similar across all three vocabulary groups; they use longer utterances than when speaking to adults, and respond faster to children than they do to other adults. However, overall pause duration varies with the vocabulary size of the children, and as a result durational aspects of the language environment to which the children are exposed differ between groups. Parents of children in the large vocabulary size group respond faster to child utterances than do parents of children in the typical vocabulary size group, who in turn respond faster to child utterances than do parents of children in the small vocabulary size group.