Children acquiring French elaborate their early verb constructions by adding adjacent morphemes incrementally at the left edge of core verbs. This hypothesis was tested with 2657 verb uses from four children between 1;3 and 2;7. Consistent with the Adjacency Hypothesis, children added clitic subjects first only to present tense forms (as in il saute ‘he jumps’); modals to infinitives (as in faut sauter ‘has to jump’); and auxiliaries to past participles (as in a sauté ‘has jumped’). Only after this did the children add subjects to the left of a modal or auxiliary, as in elle veut sauter ‘she wants to jump’, or elle a sauté ‘she has jumped’. The order in which these elements were added, and the development in the frequencies of the constructions, all support the predictions of the Adjacency Hypothesis for left edge development in early verb constructions.

While age of acquisition effects have been researched extensively in adult second language (L2) acquisition, there is less research focused on examining age of acquisition effects in child language learners. Importantly, for child learners, delays in exposure to language can occur not only for a second but also for a first language (L1). In regard to delays in exposure, it is a widespread assumption that these are detrimental to language outcomes, and that younger is always better for successful language learning. One of the aims of this special issue was to take a closer look at the evidence for this assumption with respect to language learning within the childhood years, both for delayed L1 and L2 exposure.

Using the methods of conversation analysis, the opening sequences of a map task in the interactions of sixteen children aged seven to twelve were analyzed. The analytical concerns driving the study were who started, how they started, and how children dealt with differential access to information and the identification of phases within the opening. It was found that all participants oriented to the instruction-giver as the one to start, even when the information-follower commenced the task. With respect to how to start, the older children produced a question and answer sequence or a try-mark to establish a common starting point. Five of the eight younger children inferred a common starting point on the map. Three recurring phases were identified: readiness to begin established through a discourse marker, location of the starting point, and actual instruction. The findings are discussed with reference to the importance of interaction in referential spatial tasks.

This study analyzes how others engage rural and urban Mozambican infants during naturalistic observations, and how the proportion of time spent in different engagements relates to infants' language development over the second year of life. Using an extended version of Bakeman and Adamson's (1984) categorization of infant engagement, we investigated to what extent a detailed analysis of infant engagement can contribute to our understanding of vocabulary development in natural settings. In addition, we explored how the different infant engagements relate to vocabulary size, and how these differ between the two communities. Results show that rural infants spend significantly more time in forms of solitary engagement, whereas urban infants spend more time in forms of triadic joint engagement. In regard to correlations with reported productive vocabulary, we find that dyadic persons engagement (i.e. interactions not about concrete objects) has positive correlations with vocabulary measures in both rural and urban communities. In addition, we find that triadic coordinated joint attention has a positive relationship with vocabulary in the urban community, but a contrasting negative correlation with vocabulary in the rural community. These similarities and differences are explained, based upon the parenting beliefs and socialization practices of different prototypical learning environments. Overall, this study concludes that the extended categorization provides a valuable contribution to the analysis of infant engagement and their relation to language acquisition, especially for analyzing naturalistic observations as compared to semi-structured studies. Moreover, with respect to vocabulary development, Mozambican infants appear to benefit strongest from dyadic Persons engagement, while they do not necessarily benefit from joint attention, as tends to be the case for children from industrial, developed communities.

This study explores the hypothesis that the existence of a short sensitive period for lower-level speech perception/articulation skills, and a long one for higher-level language skills, may partly explain the language outcomes of children with cochlear implants (CIs). The participants were fourteen children fitted with a CI before their second birthday. Data about their language skills and the environmental conditions (e.g. Family Involvement in rehabilitation) were obtained over a period of three years. Age at implantation correlated exclusively with the ratio of errors of place of articulation, a phonological feature for which CIs provide insufficient information. The degree of Family Involvement was significantly correlated with the remaining language measures. We conclude that small plasticity reductions affecting lower-level skills may partly explain the difficulties of some CI users in developing language.

The present study examined early vocabulary development in fifty-nine French monolingual and fifty French–English bilingual infants (1;4–1;6). Vocabulary comprehension was assessed using both parental report (MacArthur-Bates Communicative Development Inventory; CDI) and the Computerized Comprehension Task (CCT). When assessing receptive vocabulary development using parental report, the bilinguals knew more words in their L1 versus their L2. However, young bilinguals were as accurate in L1 as they were in L2 on the CCT, and exhibited no difference in speed of word comprehension across languages. The proportion of translation equivalents in comprehension varied widely within this sample of young bilinguals and was linked to both measures of vocabulary size but not to speed of word retrieval or exposure to L2. Interestingly, the monolinguals outperformed the bilinguals with respect to accuracy but not reaction time in their L1 and L2. These results highlight the importance of using multiple measures to assess early vocabulary development.

In this study we evaluated the predictive validity of conceptual scoring. Two independent samples of Spanish-speaking language minority preschoolers (Sample 1: N = 96, mean age = 54·51 months, 54·3% male; Sample 2: N = 116, mean age = 60·70 months, 56·0% male) completed measures of receptive, expressive, and definitional vocabulary in their first (L1) and second (L2) languages at two time points approximately 9–12 months apart. We examined whether unique L1 and L2 vocabulary at time 1 predicted later L2 and L1 vocabulary, respectively. Results indicated that unique L1 vocabulary did not predict later L2 vocabulary after controlling for initial L2 vocabulary. An identical pattern of results emerged for L1 vocabulary outcomes. We also examined whether children acquired translational equivalents for words known in one language but not the other. Results indicated that children acquired translational equivalents, providing partial support for the transfer of vocabulary knowledge across languages.

Generic language (Owls eat at night) expresses knowledge about categories and may represent a cognitively default mode of generalization. English-speaking children and adults more accurately recall generic than quantified sentences (All owls eat at night) and tend to recall quantified sentences as generic. However, generics in English are shorter than quantified sentences, and may be better recalled for this reason. The present study provided a new test of the issue in Spanish, where generics are expressed with an additional linguistic element not found in certain quantified sentences (Los búhos comen de noche ‘Owls eat at night’ [generic] vs. Muchos búhos comen de noche ‘Many owls eat at night’ [quantified]). Both preschoolers and adults recalled generics more accurately than quantified sentences, and quantified sentences were more often recalled as generic than the reverse. These findings provide strong additional evidence for generics as a cognitive default, in an understudied cultural context.

This study examines the comprehension of relative clauses by Chinese-speaking children, and evaluates the validity of the predictions of the Dependency Locality Theory (Gibson, 1998, 2000) and the Relativized Minimality approach (Friedmann, Belletti & Rizzi, 2009). One hundred and twenty children from three to eight years of age were tested by using a character–sentence matching task. We found a preference for subject relative clauses that persists as children grow older. This preference is predicted by the Relativized Minimality approach, but not by the Dependency Locality Theory. In addition, we observed a fine-grained class of errors in comprehension. We discuss it in the light of the head-final status of Chinese relative clauses.

English has a word-minimality requirement that all open-class lexical items must contain at least two moras of structure, forming a bimoraic foot (Hayes, 1995).Thus, a word with either a long vowel, or a short vowel and a coda consonant, satisfies this requirement. This raises the question of when and how young children might learn this language-specific constraint, and if they would use coda consonants earlier and more reliably after short vowels compared to long vowels. To evaluate this possibility we conducted an elicited imitation experiment with 15 two-year-old Australian English-speaking children, using both perceptual and acoustic analysis. As predicted, the children produced codas more often when preceded by short vowels. The findings suggest that English-speaking two-year-olds are sensitive to language-specific lexical constraints, and are more likely to use coda consonants when prosodically required.

The aim of the present study was to analyze the relative influence of age at implantation, parental expansions, and child language internal factors on grammatical progress in children with cochlear implants (CI). Data analyses used two longitudinal corpora of spontaneous speech samples, one with twenty-two and one with twenty-six children, implanted between 0;6 and 3;10. Analyses were performed on the combined and separate samples. Regression analyses indicate that early child MLU is the strongest predictor of child MLU two and two-and-a-half years later, followed by parental expansions and age at implantation. Associations between earliest MLU gains and MLU two years later point to stability of individual differences. Early type and token frequencies of determiners predict MLU two years later more strongly than early frequency of lexical words. We conclude that features of CI children's very early language have considerable predictive value for later language outcomes.

Caregiver speech is not a static collection of utterances, but occurs in conversational exchanges, in which caregiver and child dynamically influence each other's speech. We investigate (a) whether children and caregivers modulate the prosody of their speech as a function of their interlocutor's speech, and (b) the influence of the initiator of the conversation on durational characteristics of the exchange. We analyzed naturalistic conversations from 13 mother–infant/toddler dyads aged 12–30 months across full-day recordings of 3–5 days per dyad using LENA and automated analytic tools. We found small, but significant, effects of mothers and their children influencing each other's speech, particularly in pitch measures. We also found longer utterances and shorter response latencies for the initiator of a conversation. While mothers show more mature conversational capabilities (more entrainment, shorter response latencies), our findings converge with prior research to highlight the active role of young children in the conversational exchange.

This study investigated how Turkish-speaking children and adults interpret negative sentences with disjunction (English or) and ones with conjunction (English and). The goal was to see whether Turkish-speaking children and adults assigned the same interpretation to both kinds of sentences and, if not, to determine the source of the differences. Turkish-speaking children and adults were found to assign different interpretations to negative sentences with disjunction just in case the nouns in the disjunction phrase were marked with accusative case. For children, negation took scope over disjunction regardless of case marking, whereas, for adults, disjunction took scope over negation if the disjunctive phrases were case marked. Both groups assigned the same interpretation to negative sentences with conjunction; both case-marked and non-case-marked conjunction phrases took scope over negation. The findings are taken as evidence for a ‘subset’ principle of language learnability that dictates children's initial scope assignments.

A central question in language acquisition is how children build linguistic representations that allow them to generalize verbs from one construction to another (e.g., The boy gave a present to the girl → The boy gave the girl a present), whilst appropriately constraining those generalizations to avoid non-adultlike errors (e.g., I said no to her → *I said her no). Although a consensus is emerging that learners solve this problem using both statistical and semantics-based learning procedures (e.g., entrenchment, pre-emption, and semantic verb class formation), there currently exist few – if any – proposals for a learning model that combines these mechanisms. The present study used a connectionist model to test an account that argues for competition between constructions based on (a) verb-in construction frequency, (b) relevance of constructions for the speaker's intended message, and (c) fit between the fine-grained semantic properties of individual verbs and individual constructions. The model was able not only (a) to simulate the overall pattern of overgeneralization-then-retreat, but also (b) to use the semantics of novel verbs to predict their argument structure privileges (just as real learners do), and (c) to predict the pattern of by-verb grammaticality judgements observed in adult studies.

This study investigates the coordination of matrix and subordinate clauses within finite complement-clause constructions. The data come from diary and audio recordings which include the utterances produced by an American English-speaking child, L, between the ages 1;08 and 3;05. We extracted all the finite complement-clause constructions that L produced and compared the grammatical acceptability of these utterances with that of the simple sentences of the same length produced within the same two weeks and with that of the simple sentences containing the same verb produced within the same month. The results show that L is more likely to make syntactic errors in finite complement-clause constructions than she does in her simple sentences of the same length or with the same verb. This suggests that the errors are more likely to arise from the syntactic and semantic coordination of the two clauses rather than limitations in performance or lexical knowledge.

Languages differ greatly in how they express causal events. In languages like Japanese, the subjects of causative sentences, or causers, are generally animate and intentional, whereas in other languages like English, causers range widely from animate beings to inanimate objects (e.g. Wolff, Jeon & Li, 2009). This paper explores when children learn to represent cause in their native tongue and how this learning occurs over the course of development. English- and Japanese-speaking preschoolers watched animations that were caused by (i) humans acting intentionally, (ii) humans acting accidentally, (iii) objects that generate energy (e.g. a machine), and (iv) objects that do not generate energy (e.g. a tool). Children were then asked to choose a good description of the event between two options. At age three, English- and Japanese-speaking children performed the task in similar ways, attending only to the intention of causal agents; however, at age four, speakers of the two languages diverged. English speakers were more likely to accept energy-generating objects such as machines as the subject of a lexical causative sentence than Japanese speakers.

The purpose of this study was to examine attention allocation in toddlers who were late talkers and toddlers with typical language development while they were engaged in a word-learning task in order to determine if differences exist. Two-year-olds who were late talkers (11) and typically developing toddlers (11) were taught twelve novel pseudo-words for unfamiliar objects over ten training sessions. The toddlers' attention allocation during the word-learning sessions was measured as well as their comprehension of the newly learned words. Late talkers showed reduced attention allocation to objects during word-training sessions, and also comprehended fewer of the novel words than toddlers with typical language development. Attention allocation was found to be a stronger predictor of word learning as compared to cognition and auditory comprehension. Reduced attention allocation may contribute to the early lexical delay characteristic in late talkers.

Deficits in pragmatic language are central to autism spectrum disorder (ASD). Here we investigate common ground, a pragmatic language skill in which speakers adjust the contents of their speech based on their interlocutor's perceived knowledge, in adolescents with ASD and typical development (TD), using an experimental narrative paradigm. Consistent with prior research, TD participants produced shorter narrations when they shared knowledge with an interlocutor, an effect not observed at the group level in ASD. This effect was unrelated to general skills such as IQ or receptive vocabulary. In ASD, the effect was correlated with age and symptom severity: older and less severely affected participants did shorten their narratives. Several metrics (including explicit references to common ground, speech disfluencies, and communicative quality ratings) suggested that, although adolescents with ASD did not show implicit reductions in their narrative length, they were aware of common ground, and communicated differently in its presence.