Children who require augmentative and alternative communication (AAC) systems while they are in the process of acquiring language face unique challenges because they use graphic symbols for communication. In contrast to the situation of typically developing children, they use different modalities for comprehension (auditory) and expression (visual). This study explored the ability of three- and four-year-old children without disabilities to perform tasks involving sequences of graphic symbols. Thirty participants were asked to transpose spoken simple sentences into graphic symbols by selecting individual symbols corresponding to the spoken words, and to interpret graphic symbol utterances by selecting one of four photographs corresponding to a sequence of three graphic symbols. The results showed that these were not simple tasks for the participants, and few of them performed in the expected manner – only one in transposition, and only one-third of participants in interpretation. Individual response strategies in some cases lead to contrasting response patterns. Children at this age level have not yet developed the skills required to deal with graphic symbols even though they have mastered the corresponding spoken language structures.

This study compared segmental distribution patterns for consonants and vowels in English infant-directed speech (IDS) and adult-directed speech (ADS). A previous study of Korean indicated that segmental patterns of IDS differed from ADS patterns (Lee, Davis & MacNeilage, 2008). The aim of the current study was to determine whether such differences in Korean are universal or language-specific. Results indicate that consonant distribution patterns of English IDS were significantly different from English ADS. Speakers who used IDS produced fewer fricatives, affricates, nasals and liquids, but more stops and glides, than speakers who used ADS. In terms of vowels, IDS speakers produced more high-back vowels /u Ʊ/ and /ɔI/ diphthongs than ADS speakers. These results indicate both general trends and language-specific segmental distribution patterns in IDS. When compared to previous findings on ADS and IDS in Korean, these results for English give support to a more general assertion that segmental distribution patterns in IDS seem to be mediated by linguistic and cultural factors across languages.

In this study, we investigated how Mandarin-speaking children and adults interpret focus structures like Zhiyou Yuehan chi-le pingguo ‘Only John ate an apple’ and Shi Yuehan chi-de pingguo ‘It is John who ate an apple’. We found that children tended to associate focus operators zhiyou ‘only’ and shi ‘be’ with the verb phrase (VP), whereas adults uniquely associated them with the subject noun phrase (NP). To account for this difference, we propose that children initially treat focus operators as adverbials, thus ending up associating them with the VP. In order to assess our proposal, we examined children's understanding of zhiyou-constructions with negation, like Zhiyou Yuehan meiyou chi pingguo ‘Only John didn't eat an apple’. It was found that children, like adults, consistently associated the focus operator with the subject NP in this construction. The findings have an important bearing on language learnability, since negation assists children in reaching the adult-like interpretation.

During the first eighteen months of life, infants acquire and refine a whole set of new motor skills that significantly change the ways in which the body moves in and interacts with the environment. In this review article, I argue that motor acquisitions provide infants with an opportunity to practice skills relevant to language acquisition before they are needed for that purpose; and that the emergence of new motor skills changes infants' experience with objects and people in ways that are relevant for both general communicative development and the acquisition of language. Implications of this perspective for current views of co-occurring language and motor impairments and for methodology in the field of child language research are also considered.

Children find object relative clauses difficult. They show poor comprehension that lags behind production into their fifth year. This finding has shaped models of relative clause acquisition, with appeals to processing heuristics or syntactic preferences to explain why object relatives are more difficult than subject relatives. Two studies here suggest that children (age 4 ; 6) do not find all object relatives difficult: a corpus study shows that children most often hear and produce object relatives with pronominal subjects. But they are most often tested on ones with lexical-NP subjects (e.g. The nurse thatthe girlis drawing). When tested on object relatives with pronominal subjects (e.g. The nurse thatIam drawing), similar to those they actually hear and produce, Hebrew speakers aged 4 ; 6 show good comprehension (85% accuracy) that matches their production ability. This suggests a different path of relative clause acquisition, one that is sensitive to fine-grained distributional information.

How do infants find the words in the speech stream? Computational models help us understand this feat by revealing the advantages and disadvantages of different strategies that infants might use. Here, we outline a computational model of word segmentation that aims both to incorporate cues proposed by language acquisition researchers and to establish the contributions different cues can make to word segmentation. We present experimental results from modified versions of Venkataraman's (2001) segmentation model that examine the utility of: (1) language-universal phonotactic cues; (2) language-specific phonotactic cues which must be learned while segmenting utterances; and (3) their combination. We show that the language-specific cue improves segmentation performance overall, but the language-universal phonotactic cue does not, and that their combination results in the most improvement. Not only does this suggest that language-specific constraints can be learned simultaneously with speech segmentation, but it is also consistent with experimental research that shows that there are multiple phonotactic cues helpful to segmentation (e.g. Mattys, Jusczyk, Luce & Morgan, 1999; Mattys & Jusczyk, 2001). This result also compares favorably to other segmentation models (e.g. Brent, 1999; Fleck, 2008; Goldwater, 2007; Johnson & Goldwater, 2009; Venkataraman, 2001) and has implications for how infants learn to segment.

Parents' use of conventional versus unconventional labels with their two- (n=12), three- (n=12) and four-year-old children (n=12) was assessed as they talked about objects that were either known or unknown to them. For known objects, parents provided typical conventional labels casually during the conversation. For unknown objects, parents were less likely to use typical nouns as labels and marked their labels with additional information suggesting that the labels might be unconventional. Parents marked potentially unconventional labels by providing explicit statements of ignorance and paralinguistic cues of uncertainty. These patterns were strongest when the unknown objects were manufactured as opposed to homemade, possibly because manufactured objects are supposed to have conventional names that parents were unable to provide. Parents' marking of unconventional labels may help children recognize when new word forms should be treated with caution and guide their learning accordingly.

The present studies examined factors that influence children's and adults' interpretation of a novel word. Four factors are hypothesized to emphasize that a label refers to a richly structured category (also known as a ‘kind’): generic language, internal property attributions, familiar kind labels and absence of a target photograph. In Study 1, for college students (N=125), internal property attributions resulted in more taxonomic and fewer shape responses. In Study 2, for four-year-olds (N=126), the presence of generic language and familiar kind labels resulted in more taxonomic choices. Further, the presence of familiar kind labels resulted in fewer shape choices. The results suggest that, when learning new words, children and adults are sensitive to factors that imply kind reference.

Most computational models of word segmentation are trained and tested on transcripts of speech, rather than the speech itself, and assume that speech is converted into a sequence of symbols prior to word segmentation. We present a way of representing speech corpora that avoids this assumption, and preserves acoustic variation present in speech. We use this new representation to re-evaluate a key computational model of word segmentation. One finding is that high levels of phonetic variability degrade the model's performance. While robustness to phonetic variability may be intrinsically valuable, this finding needs to be complemented by parallel studies of the actual abilities of children to segment phonetically variable speech.

This paper argues for broader consideration of children's language production systems and, in that context, describes research on children's planning of syntactic structures. The research presented here measures non-fluency patterns in elicited utterances of varied syntactic type. We describe and interpret several regularities in these patterns for two groups of children (‘young’: three–five-year-olds; and ‘older’: six–eight-year-olds) and an adult comparison group. The evidence indicates a strong correspondence of adult and child responses to structural complexity, both in terms of global fluency measures and in terms of more detailed indicators of planning load. In addition, we report some specific contrasts in the patterning for children and adults that suggest disparities in processing resources and/or in local planning strategies.

Previous research has rarely compared the contributions of different underlying abilities to phonological acquisition. In this study, the auditory-visual speech perception, oro-motor and rule abstraction skills of 62 typically developing two-year olds were assessed and contrasted with the accuracy of their spoken phonology. Measures included auditory-visual speech perception, production of isolated and sequenced oro-motor movements, and verbal and non-verbal rule abstraction. Abilities in all three domains contributed to phonological acquisition. However, the use of atypical phonological rules was associated with lower levels of phonological accuracy and a linear regression indicated that this measure of rule abstraction had greater explanatory power than the measures of input processing and output skill.

Research using online comprehension measures with monolingual children shows that speed and accuracy of spoken word recognition are correlated with lexical development. Here we examined speech processing efficiency in relation to vocabulary development in bilingual children learning both Spanish and English (n=26 ; 2 ; 6). Between-language associations were weak: vocabulary size in Spanish was uncorrelated with vocabulary in English, and children's facility in online comprehension in Spanish was unrelated to their facility in English. Instead, efficiency of online processing in one language was significantly related to vocabulary size in that language, after controlling for processing speed and vocabulary size in the other language. These links between efficiency of lexical access and vocabulary knowledge in bilinguals parallel those previously reported for Spanish and English monolinguals, suggesting that children's ability to abstract information from the input in building a working lexicon relates fundamentally to mechanisms underlying the construction of language.

Previous research has used cross-linguistic priming methodology with bilingual adults to explore the nature of their syntactic representations. The present paper extends the use of this methodology to bilingual children to investigate the relation between the syntactic structures of their two languages. Specifically, we examined whether the use of passives by the experimenter in one language primed the subsequent use of passives by the child in the other language. Results showed evidence of syntactic priming from Spanish to English: hearing a Spanish sentence containing a passive led to the increase in children's production of the parallel structure in English. However, there was no priming in the other direction: hearing an English sentence containing a passive did not increase children's use of the parallel structure in Spanish. These results provide evidence for both the integration of syntactic representations in bilingual children and the asymmetry of the relation between their two languages.

When they see a familiar object and an unfamiliar one, and are asked to select the referent of a novel label, children usually choose the unfamiliar object. We asked whether this ‘disambiguation effect’ reflects an expectation that each object has just one label (mutual exclusivity), or an expectation about the intent of the speaker who uses a novel label. In Study 1, when a speaker gazed at or pointed toward the familiar object in a novel–familiar pair, children aged 2 ; 6 (N=64) selected that object in response to a neutral request, but were much less likely to do so in response to a label request. In Study 2, when a speaker both gazed at and pointed toward the familiar object, toddlers (N=16) overwhelmingly selected the familiar object in response to a label request. The expectation that each object has just one label can lead children to discount some individual behavioral cues to a speaker's intent, though it can be overridden given a combination of pragmatic cues.

This paper investigates the distribution of imperfective and perfective verb inflections in Kuwaiti Arabic. Spontaneous speech of three children (1 ; 8–3 ; 1) was analyzed for accuracy and error types. The results showed that the verbal inflections appeared correct almost all the time (89–97% of the time). Agreement errors appeared 3–11% of the time. The children did not inflect the verb in obligatory contexts in describing ongoing action 2–12% of the time. It is predicted that children acquiring Arabic would select a default form in place of fully inflected forms. The children used a non-finite form which is identical to the imperfective verbal bare stem to describe ongoing action, which is consistent with Benmamoun's argument (1999, 2000) that the imperfective bare verb is the default form in Arabic. The findings of the study are discussed in the light of the Optional Infinitive (OI) stage argued by Wexler (1994, 1996, 1998). The fact that the non-finite is non-tensed makes this type of behavior consistent with the OI.

There are numerous models of how speech segmentation may proceed in infants acquiring their first language. We present a framework for considering the relative merits and limitations of these various approaches. We then present a model of speech segmentation that aims to reveal important sources of information for speech segmentation, and to capture psycholinguistic constraints on children's language perception. The model constructs a lexicon based on information about utterance boundaries and deduces phonotactic constraints from the discovered lexicon. Compared to other models of speech segmentation, our model performs well in terms of accuracy, computational tractability and the number of components of the model. Finally, our model also reflects the psycholinguistic effects of language learning, in terms of the early advantage for segmentation provided by the child's name, and by revealing the overlap in usefulness of information for segmentation and for grammatical categorization of the language.