Children with pre/perinatal unilateral brain lesions (PL) show remarkable plasticity for language development. Is this plasticity characterized by the same developmental trajectory that characterizes typically developing (TD) children, with gesture leading the way into speech? We explored this question, comparing eleven children with PL – matched to thirty TD children on expressive vocabulary – in the second year of life. Children with PL showed similarities to TD children for simple but not complex sentence types. Children with PL produced simple sentences across gesture and speech several months before producing them entirely in speech, exhibiting parallel delays in both gesture + speech and speech-alone. However, unlike TD children, children with PL produced complex sentence types first in speech-alone. Overall, the gesture–speech system appears to be a robust feature of language learning for simple – but not complex – sentence constructions, acting as a harbinger of change in language development even when that language is developing in an injured brain.

The aim of this study was to determine, using speech error and articulatory analyses, whether the binary distinction between iambs and trochees should be extended to include additional prosodic subcategories. Adults, children who are normally developing, and children with specific language impairment (SLI) participated. Children with SLI were included because they exhibit prosodic and motor deficits. Children, especially those with SLI, showed the expected increase in omission errors in weak initial syllables. Movement patterning analyses revealed that speakers produced differentiated articulatory templates beyond the broad categories of iamb and trochee. Finally, weak–weak prosodic sequences that crossed word boundaries showed increased articulatory variability when compared with strong–weak alternations. The binary distinction between iamb and trochee may be insufficient, with additional systematic prosodic subcategories evident, even in young children with SLI. Findings support increased interactivity in language processing.

This study reports on language outcomes at eight years from the Bucharest Early Intervention Project, a randomized controlled study of foster care. We previously have shown that children placed in foster care by age two have substantially stronger preschool language outcomes than children placed later and children remaining in institutional care. One hundred and five children participated in the current study, fifty-four originally assigned to foster care and fifty-one to continued institutional care. Even though current placements varied, children originally in foster care had longer sentences and stronger sentence repetition and written word identification. Children placed in foster care by age two had significant advantages in word identification and nonword repetition; children placed by age 1 ; 3 performed equivalently to community peers. The results show the continuing adverse effects of early poor institutional care on later language development and the key importance of age of placement in a more optimal environment.

Children typically acquire their native language naturally and spontaneously at a very young age. The emergence of early grammar can be predicted from children's vocabulary size and composition (Bates et al., 1994; Bates, Bretherton & Snyder, 1998; Bates & Goodman, 1997). One central question in language research is understanding what causes the changes in early language acquisition. Some researchers argue that the qualitative and quantitative shifts in word learning simply reflect the changing character of the child's cognitive maturity (for example, Gentner, 1982), while others argue that the trajectory of early language acquisition is driven by the child's growing familiarity with the language (Gillette, Gleitman, Gleitman & Lederer, 1999; Snedeker & Gleitman, 2004). These hypotheses are difficult to adjudicate because language acquisition in virtually all hearing children begins from birth and occurs simultaneously with cognitive development and brain maturation. The acquisition of sign languages, in contrast, is frequently delayed until older ages. In the USA, over 90% of deaf children are born to hearing parents who do not use sign language (Schein, 1989). As a result, deaf children are often exposed to sign language as a first language at a range of ages well beyond infancy (Mayberry, 2007). In rare cases, some deaf individuals are isolated from all linguistic input until adolescence when they start receiving special services and begin to learn sign language through immersion (Morford, 2003). Case studies of language acquisition in such extreme late first-language (L1) learners provide a unique opportunity to investigate first-language learning. The current study investigates three cases of young teens who are in the early stages of acquiring American Sign Language (ASL) as a first language, to determine what first-language acquisition in adolescence looks like.

This longitudinal study examined the predictive validity of the MacArthur Communicative Developmental Inventories-Short Form (CDI-SF), a parent report questionnaire about children's language development (Fenson, Pethick, Renda, Cox, Dale & Reznick, 2000). Data were first gathered from parents on the CDI-SF vocabulary scores for seventy-six children (mean age=1 ; 10). Four years later (mean age=6 ; 1), children were assessed on language outcomes (expressive vocabulary, syntax, semantics and pragmatics) and code-related skills, including phonemic awareness, word recognition and decoding skills. Hierarchical regression analyses revealed that early expressive vocabulary accounted for 17% of the variance in picture vocabulary, 11% of the variance in syntax, and 7% of the variance in semantics, while not accounting for any variance in pragmatics in kindergarten. CDI-SF scores did not predict code-related skills in kindergarten. The importance of early vocabulary skills for later language development and CDI-SF as a valuable research tool are discussed.

Most evidence concerning cross-linguistic variation in noun bias, the preponderance of nouns in early expressive lexicons (Gentner, 1982), has come from comparisons of monolingual children acquiring different languages. Such designs are susceptible to a number of potential confounders, including group differences in developmental level and sociodemographic characteristics. The aim of this study was to quantify noun bias in bilingual Mandarin–English toddlers whose expressive lexicons in each language contained 50–300 words. Parents of fifty children (1;10–2;6) reported separately on their English and Mandarin expressive lexicons. The mean percentage of Mandarin nouns (38%) was significantly lower than the percentage of English nouns (54%) and was robust to analyses of twelve potential covariates. Analyses of the most frequently reported words suggested that lexical reduplication could be considered as a potential influence on vocabulary composition in future studies. Results suggest that characteristics of the input significantly shape early lexicons.

The interpretation of floating quantifiers in Japanese requires knowledge of hierarchical phrase structure. However, the input to children is insufficient or even misleading, as our analysis indicates. This presents an intriguing question on learnability: do children interpret floating quantifiers based on a structure-dependent rule which is not obvious in the input or do they employ a sentence comprehension strategy based on the available input? Two experiments examined four- to six-year-old Japanese-speaking children for their interpretations of floating quantifiers in SOV and OSV sentences. The results revealed that no child employed a comprehension strategy in terms of the linear ordering of constituents, and most five- and six-year-olds correctly interpreted floating quantifiers when word-order difficulty was reduced. These facts indicate that children's interpretation of floating quantifiers is structurally dependent on hierarchical phrase structure, suggesting that this knowledge is a part of children's grammar despite the insufficient input available to them.

This is a naturalistic study of the development of language in Hebrew-speaking children with Williams syndrome (WS) and children with Down syndrome (DS), whose MLU extended from 1·0 to 4·4. Developmental curves over the entire span of data collection revealed minor differences between children with WS, children with DS, and typically developing (TD) controls of similar MLU. Development within one calendar year showed remarkable synchrony among the variables. However, age of language onset and pace of acquisition departed significantly from normal timing. It is argued that in view of the centrality of genetic timing and the network properties of cognition, normal schedules are crucial determinants of intact development. Consequently, with respect to neurodevelopmental syndromes, the so-called ‘language delay’ is indicative of deviance that is likely to impact development in critical ways.

The aims of the study were to establish whether there is a correlation between the socioeconomic background of Afrikaans-speaking children and their performance on a dialect-neutral language test, and to ascertain whether the allowance the test currently makes for parental education level is sufficient. The Afrikaans version of the Diagnostic Evaluation of Language Variation (Seymour, Roeper & de Villiers, 2005a) was administered to 231 Afrikaans-speaking children age 4 ; 0 to 9 ; 11 from various socioeconomic backgrounds. A positive correlation was found between the composite language scores as well as the scores for each of the language domains (syntax, pragmatics, semantics) and the primary female caregivers' highest level of education. Children with father figures present did not outperform those without. It appears that the original manner of accommodating parental education level in interpreting the children's language scores on the test is sufficient and need not be refined for the South African context.

The present study focuses on the characteristics of parental child-directed communication and its relationship with child language development. For this purpose, thirty-six toddlers (18 males and 18 females) and their parents were observed in a laboratory during triadic free play at ages 1 ; 3 and 1 ; 9. The characteristics of the maternal and paternal child-directed language (characteristics of communicative functions and lexicon as reported in psycholinguistic norms for Italian language) were coded during free play. Child language development was assessed during free play and at ages 2 ; 6 and 3 ; 0 using the Italian version of the MacArthur-Bates Communicative Development Inventory (2 ; 6) and the revised Peabody Picture Vocabulary Test (PPVT-R) (3 ; 0). Data analysis indicated differences between mothers and fathers in the quantitative characteristics of communicative functions and language, such as the mean length of utterances (MLU), and the number of tokens and types. Mothers also produced the more frequent nouns in the child lexicon. There emerged a relation between the characteristics of parental child-directed language and child language development.

In this article we report two studies: a detailed longitudinal analysis of errors in wh-questions from six German-learning children (age 2 ; 0–3 ; 0) and an analysis of the prosodic characteristics of wh-questions in German child-directed speech. The results of the first study demonstrate that German-learning children frequently omit the initial wh-word. A lexical analysis of wh-less questions revealed that children are more likely to omit the wh-word was (‘what’) than other wh-words (e.g. wo ‘where’). In the second study, we performed an acoustic analysis of sixty wh-questions that one mother produced during her child's third year of life. The results show that the wh-word was is much less likely to be accented than the wh-word wo, indicating a relationship between children's omission of wh-words and the stress patterns associated with wh-questions. The findings are discussed in the light of discourse–pragmatic and metrical accounts of omission errors.

Acquisition of English grammatical morphology was examined in five internationally adopted (IA) children from China (aged 0;10–1;1 at adoption) during the first three years' exposure to English to determine whether acquisition patterns were characteristic of child second language (L2) learners or monolingual first language (L1) learners. Results from spontaneous and elicited speech showed that IA children acquired grammatical morphemes similarly to L1 learners; namely, (1) non-tense-marking morphemes were acquired earlier than tense-marking morphemes; (2) BE was acquired in synchrony with other tense-marking morphemes; and (3) a high percentage of omission errors and a low percentage of commission errors were observed.

Children start producing if p, q conditionals relatively late. Past counterfactuals (PCFs), for example ‘If she had shut the cage, the rabbit wouldn't have escaped’, are particularly problematic for children; despite evidence of comprehension in the preschool years, children aged eleven are still making production errors in PCF structure (Crutchley, 2004). Working within a usage-based framework, the present study explores whether PCFs in the conversational component of the British National Corpus show structural similarities to the set of PCF structures produced by six- to eleven-year-old children in an elicitation task. Adult PCFs are found to be both rare in spontaneous conversation and very varied in structure. Low token frequency and high type frequency are hypothesized to account partly for children's late acquisition of the PCF construction. However, regularities in the use of subjects and verbs in adult PCFs are hypothesized to assist children's acquisition of the construction.

This study examined the production of three types of noun plural inflections, feminine sound plural (FSP), masculine sound plural (MSP), and broken plural (BP) in Kuwaiti Arabic-speaking children with and without language impairment. A total of thirty-six Kuwaiti participants – twelve adults, twelve children with specific language impairment (SLI), and twelve typically developing age-matched controls (TD) were presented with twenty-seven pictured stimuli of real and nonsense words. The results showed that the TD children were significantly more accurate in using the required noun plural inflections than the SLI group. The TD children's preferred overgeneralization strategy was to substitute FSP for the regular MSP and irregular BP contexts much more than their peers with SLI. The performance of the SLI group also differed from that of their age-matched counterparts in the number of errors and their distribution across categories. The results are discussed in the light of relevant theories of atypical language development.

One important mechanism suggested to underlie the acquisition of grammar is rule learning. Indeed, infants aged 0 ; 7 are able to learn rules based on simple identity relations (adjacent repetitions, ABB: “wo fe fe” and non-adjacent repetitions, ABA: “wo fe wo”, respectively; Marcus et al., 1999). One unexplored issue is whether young infants are able to process both adjacent and non-adjacent repetitions. As the previous studies always compared the two types of repetition structures directly, the ability to learn only one of them was sufficient for successful discrimination in these tasks. The present study reports two experiments, in which we test the ability of infants aged 0 ; 7 to discriminate adjacent and non-adjacent repetition structures against random controls (ABB vs. ABC and ABA vs. ABC). We show that, contrary to some previous proposals, infants aged 0 ; 7 successfully discriminate both repetition types from random controls, but show no spontaneous preference for either of them.

Young children answer many questions every day. The extent to which they do this in an adult-like way – following Grice's Maxim of Quantity by providing the requested information, no more no less – has been studied very little. In an experiment, we found that two-, three- and four-year-old children are quite skilled at answering argument-focus questions and predicate-focus questions with intransitives in which their response requires only a single element. But predicate-focus questions for transitives – requiring both the predicate and the direct object – are difficult for children below four years of age. Even more difficult for children this young are sentence-focus questions such as “What's happening?”, which give the child no anchor in given information around which to structure their answer. In addition, in a corpus study, we found that parents ask their children predicate-focus and sentence-focus questions very infrequently, thus giving children little experience with them.

This study tested whether bilingual children show a lag in semantic development (the schematic–categorical shift) relative to monolingual children due to smaller vocabularies within a language. Twenty French–English bilingual and twenty English monolingual children (seven to ten years old) participated in a picture-naming task in English. Their errors were coded for schematic or categorical relations. The bilingual children made more schematic errors than monolinguals, a difference that was accounted for statistically by vocabulary score differences. This result suggests that within-language vocabulary size is one important factor in semantic development and may explain why bilingual children sometimes show a lag relative to monolingual children in one of their languages, perhaps the language in which they have received less formal instruction.

What are the sources of variation in the input, and how much do they matter for language acquisition? This study examines frequency variation in manner-of-articulation classes in child and adult input. The null hypothesis is that segmental frequency distributions of language varieties are unigram (modelable by stationary, ergodic processes), and that languages are unitary (modelable as a single language variety). Experiment I showed that English segments are not unigram; they exhibit a ‘bursty’ distribution in which the local frequency varies more than expected by chance alone. Experiment II showed the English segments are approximately unitary: the natural background variation in segmental frequencies that arises within a single language variety is much larger than numerical differences across varieties. Variation in segmental frequencies seems to be driven by variation in discourse topic; topic-associated words cause bursts/lulls in local segmental frequencies. The article concludes with some methodological recommendations for comparing language samples.

The talk children hear from their primary caregivers predicts the size of their vocabularies. But children who spend time with multiple individuals also hear talk that others direct to them, as well as talk not directed to them at all. We investigated the effect of linguistic input on vocabulary acquisition in children who routinely spent time with one vs. multiple individuals. For all children, the number of words primary caregivers directed to them at age 2 ; 6 predicted vocabulary size at age 3 ; 6. For children who spent time with multiple individuals, child-directed words from all household members also predicted later vocabulary and accounted for more variance in vocabulary than words from primary caregivers alone. Interestingly, overheard words added no predictive value to the model. These findings suggest that speech directed to children is important for early word learning, even in households where a sizable proportion of input comes from overheard speech.

Previous research has shown that high phonotactic frequencies facilitate the production of regularly inflected verbs in English-learning children with specific language impairment (SLI) but not with typical development (TD). We asked whether this finding can be replicated for German, a language with a much more complex inflectional verb paradigm than English. Using an elicitation task, the production of inflected nonce verb forms (3rd person singular with -t suffix) with either high- or low-frequency subsyllables was tested in sixteen German-learning children with SLI (ages 4;1–5;1), sixteen TD-children matched for chronological age (CA) and fourteen TD-children matched for verbal age (VA) (ages 3;0–3;11). The findings revealed that children with SLI, but not CA- or VA-children, showed differential performance between the two types of verbs, producing more inflectional errors when the verb forms resulted in low-frequency subsyllables than when they resulted in high-frequency subsyllables, replicating the results from English-learning children.