The acquisition of colour terms in pre-school-aged children was investigated in two studies. The first study explored the role of conceptual factors in 2-, 3- and 4-year-old children's performance on two tasks. Comprehension and production of basic colour words were tested using stimuli that varied in focality. The results confirmed earlier research demonstrating the important and early influence of focality on children's colour concepts and developing colour lexicon. However, only moderate support was obtained for the order-of-acquisition hypothesis proposed by Berlin & Kay (1969). Quite large discrepancies between comprehension and production were found in this study, with no clear relationship between these two performances. In the second study the role of maternal input on children's learning of colour words was investigated, using the spontaneous speech transcripts from Adam, Eve and Sarah. Significant correlations between mothers' and children's uses of specific colour words were found across all three subjects. The findings from both studies confirm that both conceptual and environmental factors are important in shaping the child's developing colour concepts and colour lexicon, particularly for mapping out the boundaries of the basic colour spaces, which are culturally, rather than innately, determined.

Children who acquire Dutch as their first language show a strong preference for using infinitival verb forms during the early stages of grammatical development. This exemplifies the ‘root infinitive’ (RI) phenomenon, which has played a significant role in recent discussions on the development of syntax. Most accounts proposed thus far invoke an immaturity of the child's grammatical competence. We explore the possibility that the early predominance of infinitival forms is related to patterns in the language input. We analysed a corpus of utterances addressed by two Dutch-speaking mothers to their two- to three-year old sons. Root infinitive utterances amounted to 10%, and auxiliary-plus infinitive main verb constructions, which in terms of word order are maximally similar to RIs, constituted 30% of all verb-containing utterances. These figures render an account in terms of exposure to utterance structures unlikely. There is a moderate (but significant) correlation between frequency of occurrence of individual verb forms in the input and age of acquisition. However, infinitive verb forms are often acquired earlier than their input frequency would predict, and this may be related to an overall increased salience, due to their systematic appearance in sentence-final position and their relatively high conceptual transparency as compared to finite verbs.

The emergence of grammar in relation to lexical growth was analyzed in a sample of Finnish children (N=181) at 2 ; 0. The Finnish version of the Communicative Development Inventory was used to gather information on both language domains. The onset of grammar occurred in close association with vocabulary growth. The acquisition of the nominal and verbal inflections of Finnish differed when analyzed in relation to the lexicon in which they are used: the strongest growth in the acquisition of case form types occurred when the nominal lexicon size was roughly between 50 and 250 words, whereas verb inflectional types were acquired actively from the beginning of the verb lexicon acquisition. The findings extend the previous findings of the close association between lexicon and grammar (e.g. Bates & Goodman, 1999). The results suggest that different grammatical structures display different degrees and types of lexical dependency.

This paper presents a study of children's ability to recognize the presuppositions of sentences with factive and nonfactive verbs, and a review of recent research on the acquisition of factive presuppositions. In the present study, subjects in grades K, 2, 5 and 8, and adults, were asked to judge the truth of the complement clauses of sentences of the form ‘Doctor Fact (verb) that the ball is (is not) blue.’ The task was presented in the context of a television quiz show, with subjects as putative contestants. A tendency was found among younger subjects to overgeneralize the scope of negation of complement verbs into the main clauses of factive sentences. A gradual increase in comprehension of factive and nonfactive verbs was found, extending into adolescence. In a comparison of the present results with those of several recent studies, marked differences were found in the age of acquisition of factivity. These differences are discussed in terms of variations in task requirements and assessment techniques. It is concluded that acquisition proceeds on a verb-by-verb basis, rather than as a unitary process.

Speech samples from eight British female adults addressing young children and another adult were analysed in terms of vocal pitch. Increases in vocal pitch when addressing young children were observed but were smaller than the increases noted by North American researchers, and variability across speakers was marked. Some adults only slightly raised their vocal pitch to young children. Pitch increases were generally more marked for mean as against modal pitch measures, and for free speech as against reading aloud conditions.

The current study attempts to differentiate effects of phonotactic probability (i.e. the likelihood of occurrence of a sound sequence), neighbourhood density (i.e. the number of phonologically similar words), word frequency, and word length on expressive vocabulary development by young children. Naturalistic conversational samples for three children (age 1;4–3;1) were obtained from CHILDES. In a backward regression analysis, phonotactic probability, neighbourhood density, word frequency, and word length were entered as possible predictors of ages of first production of words for each child. Results showed that the factors affecting first production of words varied across children and across word types. Specifically, word length affected ages of first production for all three children, whereas the other three variables affected only one child each. The implications of these findings for models of expressive vocabulary development are discussed.

Little research has explored how preschools can support children's second-language (L2) vocabulary development. This study keenly followed the progress of twemty-six Turkish immigrant children growing up in Norway from preschool (age five) to fifth grade (age ten). Four different measures of preschool talk exposure (amount and diversity of teacher-led group talk and amount and diversity of peer talk), as well as the demographic variables of maternal education and co-ethnic concentration in the neighborhood, were employed to predict the children's L2 vocabulary trajectories. The results of growth analyses revealed that maternal education was the only variable predicting children's vocabulary growth during the elementary years. However, teacher-led talk, peer talk, and neighborhood predicted children's L2 vocabulary skills at age five, and these differences were maintained up to age ten. This study underscores the importance of both preschool talk exposure (teacher-led talk and peer talk) and demographic factors on L2 learners' vocabulary development.

This paper reports progress in developing a computer model of language acquisition in the form of (1) a generative grammar that is (2) algorithmically learnable from realistic corpus data, (3) viable in its large-scale quantitative performance and (4) psychologically real. First, we describe new algorithmic methods for unsupervised learning of generative grammars from raw CHILDES data and give an account of the generative performance of the acquired grammars. Next, we summarize findings from recent longitudinal and experimental work that suggests how certain statistically prominent structural properties of child-directed speech may facilitate language acquisition. We then present a series of new analyses of CHILDES data indicating that the desired properties are indeed present in realistic child-directed speech corpora. Finally, we suggest how our computational results, behavioral findings, and corpus-based insights can be integrated into a next-generation model aimed at meeting the four requirements of our modeling framework.

Past research has indicated that English-learning infants begin segmenting words from speech by 7·5 months of age (Jusczyk & Aslin, 1995). More recent work has demonstrated, however, that 7·5-month-olds' segmentation abilities are severely limited. For example, the ability to segment vowel-initial words from speech reportedly does not appear until 13·5 to 16 months of age (Mattys & Jusczyk, 2001; Nazzi, Dilley, Jusczyk, Shattuck-Hufnagel & Jusczyk, 2005). In this paper, we report on three experiments using the Headturn Preference procedure that investigate both phonetic and phonological factors influencing 11-month-olds' segmentation of vowel-initial words from speech. We replicate earlier findings suggesting that infants have difficulty segmenting vowel-initial words from speech. In addition we extend these findings by demonstrating that under certain conditions, infants are capable of segmenting vowel-initial words from speech at a much younger age than earlier studies have reported. Our findings suggest that infants' ability to segment vowel-initial words from speech is tightly constrained by acoustic-phonetic factors such as pitch movement at the onset of vowel-initial words and segmental strengthening. These experiments underscore the complexity of early word segmentation, and highlight the importance of including contextual factors in developmental models of word segmentation.

The present study investigates the performance of 96 Cantonese-speaking three- to five-year-old preschoolers on three false belief tasks – a deceptive object, a change of location, and an unexpected contents task encompassing a variety of task factors. Most importantly, the research examines the possibility that false belief performance depends on specific linguistic factors such as the type of verb used in the test question – an explicitly false vs. a neutral belief verb. Cantonese was chosen as particularly useful for examining this question because it explicitly codes belief status as either neutral (nam5) or false (ji5wai4), and because it offers additional linguistic and cultural contrasts to research conducted on false belief with children learning English and other Indo-European languages. As expected, a strong age effect was found, as well as a significant advantage for children who received the explicit false belief (ji5wai4) wording and for those who were asked to explain rather than predict the protagonist's actions. Interestingly, there was also a strong task difference with children performing better on the deceptive object task than on the other two false belief tasks. We argue that these results point both to universal trajectories in theory of mind development and to interesting, but localized, effects of language and culture on children's false belief understanding.

This paper investigates the development of relative clauses in the speech of one German-speaking child aged 2 ; 0 to 5 ; 0. The earliest relative clauses we found in the data occur in topicalization constructions that are only a little different from simple sentences: they contain a single proposition, express the actor prior to other participants, assert new information and often occur with main-clause word order. In the course of the development, more complex relative constructions emerge, in which the relative clause is embedded in a fully-fledged main clause. We argue that German relative clauses develop in an incremental fashion from simple non-embedded sentences that gradually evolve into complex sentence constructions.

Previous studies on children's pragmatic abilities have tended to focus on just one pragmatic phenomenon and one expressive means at a time, mainly concentrating on comprehension, and overlooking the production side. We assessed both comprehension and production in relation to several pragmatic phenomena (simple and complex standard communication acts, irony, and deceit) and several expressive means (linguistic, extralinguistic, paralinguistic). Our study involved 390 Italian-speaking children divided into three age groups: 5;0–5;6, 6;6–7;0, and 8;0–8;6. Children's performance on all tasks improved with their age. Within each age group, children responded more accurately to tasks involving standard communication than to those involving deceit and irony, across all expressive means and for both comprehension and production. Within each pragmatic phenomenon, children responded more accurately to simple acts than to complex ones, regardless of age group and expressive means, i.e., linguistic or extralinguistic. Overall results fit well with the Cognitive Pragmatics theory (Bara, 2010).

The study was aimed at determining the average ages at which children imitate (I), produce (P) and comprehend (C) passive constructions. The results were compared with those obtained from partial studies of the acquisition of the passive voice conducted by researchers such as Fraser, Bellugi & Brown (1963). The finding that imitation precedes comprehension which in turn precedes production (I > C > P), as reported by Fraser et al. (1963) for 12 three-year-olds, is confirmed in this study for children from 3; 0 to 8; 0. The ability to use the passive voice in various tasks was found to be generally greater than that suggested in previous studies.

The acquisition of noun gender on articles was studied in a sample of 21 young German-speaking children. Longitudinal spontaneous speech data were used. Data analysis is based on 22 two-hourly speech samples per child from 6 children between 1 ; 4 and 3 ; 8 and on 5 two-hourly speech samples per child from 15 children between 1 ; 4 and 2 ; 10. The use of gender marked articles occurred from 1 ; 5. Error frequencies dropped below 10% by 3 ; 0. Definite and indefinite articles were used with similar frequencies and error rates did not differ in the two paradigms. Children's errors were systematic. For monosyllabic nouns and for polysyllabic nouns ending in -el, -en and -er errors were more frequent for nouns which did not conform to the rule that such nouns tend to be masculine. Furthermore, children erred in the direction of the rule overgeneralizing der. Correct gender marking was also associated with adult frequency of noun use. The present data is evidence for the early use of phonological regularities of noun structure in the acquisition of gender marking.

Although most English-speaking children master the correct use of first and second person pronouns by three years, some children show persistent reversal errors in which they refer to themselves as you and to others as me. Recently, such differences have been attributed to the relative availability of overheard speech during the learning process. The present study tested this proposal with feed-forward neural networks learning these pronouns. Network learning speed and analysis of their knowledge representations confirmed the importance of exposure to shifting reference provided by overheard speech. Errorless pronoun learning was linked to the amount of overheard speech, interactions with a greater number of speakers, and prior knowledge of the basic-level kind PERSON.

The acquisition of the English past tense inflection is the paradigm example of rule learning in the child language literature and has become something of a test case for theories of language development. This is unfortunate, as the idiosyncratic properties of the English system of marking tense make it a rather unrepresentative example of morphological development. In this paper, I contrast this familiar inflection with a much more complex morphological subsystem, the Polish genitive. The genitive case has three different markers, each restricted to a different subset of nouns, in both the singular and the plural. Analysis of the spontanous speech of three children between the ages of 1;4 and 4;11 showed that they generalized, and overgeneralized, all three singular endings. However, error rates were extremely low and there is no evidence that they treated any one ending as the ‘default’. The genitive plural, on the other hand, showed a strikingly different pattern of acquisition, similar to that seen in English-speaking children learning the past tense. It is argued that in the latter two cases, the default-like character of one of the affixes is attributable to the properties of the relevant inflectional subsystems, not to the predispositions that children bring to the language-learning task.

Defining is a metalinguistic skill. This study charts the development of the ability to define. A total of 120 participants (40 at each of the ages of 10, 14 and 18 years) defined eight concrete and eight abstract nouns. Each definition was coded to identify the types of responses present in it. Results indicate that there are significant differences in the way concrete and abstract nouns are defined. All three age-groups defined concrete nouns mainly by class and characteristic responses. But it was not until age 18 that abstract nouns were defined by class and characteristic responses. The development of abstract noun definitions follows the development of concrete noun definitions. The ability to define is dependent upon knowledge of the meaning of the word but it is also dependent upon implicit or explicit knowledge of the definitional form. The ability to define abstract nouns is a late developing metalinguistic skill.

The present paper reports a case-study of a normally developing boy who made pronominal errors for about ten months. Comprehension and production of first- and second-person pronouns were longitudinally examined from 1; 7 to 2; 10 to test three hypotheses concerning pronominal errors: pronominal errors are a result of either (a) semantic confusion, (b) simple imitation, or (c) confusion between self and others. The results showed that the child began using first- and second-person pronouns at about 1; 8 and mastered the correct usage by 2; 10. Consistent errors for the first- and the second-person pronouns were observed from 1; 11 to 2; 4, but proportions of errors occurring in his imitative language were low. The comprehension and production data clearly indicated that the child persistently made pronominal errors due to semantic confusion. That is, first-person pronouns referred to a person with whom the child conversed and second-person pronouns referred to himself.

The present study explored children's perceptual capabilities with regard to the temporal acoustic cue of differential vowel duration, comparing children's perceptual identifications to those of adults. Three-year-old children, six-year-old children, and adults participated in two experiments, in which they were asked to identify (as voiced or voiceless) CVC words with uniformly voiceless final obstruents, but in which vowel duration was systematically varied. Children were also asked to identify a set of CONTROL stimuli, in which both closure voicing and vowel duration differences were present. Results indicate that both subject age and vowel duration of the TEST stimuli significantly affect identification responses. Adults and six-year olds evidence perceptual cross-over in their judgements for the TEST stimuli, while three-year-olds do not seem to change their identifications, regardless of variations in vowel duration. However, for both groups of children, the accuracy of identifications was greater for originally voiced stimuli on the CONTROL set of words, in which more than one potential cue to the voicing distinction was present. These results suggest that there is a complex and somewhat paradoxical relationship between developing production and perception which deserves further research. Children may consistently produce a phonetic difference (vowel duration) which they are unable to use as the SOLE perceptual cue for a phonological contrast.

Researchers have long been puzzled by children's variable omission of grammatical morphemes, often attributing this to a lack of semantic or syntactic competence. Recent studies suggest that some of this variability may be due to phonological constraints. This paper explored this issue further by conducting a longitudinal study of five English-speaking one- to two-year-olds' acquisition of articles. It found that most children were more likely to produce articles when these could be produced as part of a disyllabic foot. However, acoustic analysis revealed that one child initially produced all articles as independent prosodic words. These findings confirm that some of the variable production of articles is conditioned by constraints on children's early phonologies, providing further support for the Prosodic Licensing Hypothesis. They also hold important implications for our understanding of the emergence of syntactic knowledge.