We are extremely pleased and honoured to be taking over as co-editors of the Journal of Child Language. We follow an impressive list of previous editors. We know it will be a challenging role, but we are excited by the challenge and look forward to working together to meet it.

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.

Schaeffer (1997, 2000) argues that children lack knowledge of specificity because Dutch children omit determiners and fail to scramble pronouns. Avrutin & Brun (2001), however, find that Russian children place arguments correctly according to whether they are specific or non-specific. This paper investigates object agreement and specificity in early Swahili. Object agreement in Swahili is obligatory when the object is specific, but is prohibited when the object is non-specific. Analysis of naturalistic data from four Swahili-speaking children (1;8–3;2) reveals that children overwhelmingly provide object agreement in obligatory contexts (when the object is a personal name, is topicalized, or refers to first/second person). The supply of object agreement cannot be due to a general strategy of overusing agreement, since object agreement does not occur in prohibited contexts such as intransitive clauses. I conclude that object agreement and knowledge of specificity are acquired by Swahili children before the age of two years.

The publishers should like to apologise for a typographical error in the May 2006 issue of Journal of Child Language, Volume 33, Number 2.

In the article* on pages 303–320, an additional author was erroneously added to the article.

The correct title, authors and their affiliations should read:

Learning to use demonstratives in conversation: what do language specific strategies in Turkish reveal?

AYLİN C. KÜNTAY

Koç University, Istanbul

AND

ASLI ÖZYÜREK

Koç University, Istanbul and Max Planck Institute for Psycholinguistics, Nijmegen

The electronic version of the article on Cambridge Journals Online has been revised to include the correction.

In the current debate about the abstractness of children's early grammatical knowledge, Tomasello & Abbott-Smith (2002) have suggested that children might first develop ‘weak’ or ‘partial’ representations of abstract syntactic structures. This paper attempts to characterize these structures by comparing the development of constructions around verbs in Tomasello's (1992) case study of Travis, with those of 10 children (Stage I–II) in a year-length, longitudinal study. The results show some evidence that children's early knowledge of argument structure is verb-specific, but also some evidence that children can generalize knowledge about argument structure across verbs. One way to explain these findings is to argue that children are learning limited scope formulae around high frequency subjects and objects, which serve as building blocks for more abstract structures such as S+V and V+O. The implication is that children may have some verb-general knowledge of the transitive construction as early as Stage I, but that this knowledge is still far from being fully abstract knowledge.

Japanese provides a valuable contrast for crosslinguistic studies of noun and verb dominance in early child language, and the effect of input on the early lexicon. In this study, 31 Japanese children between 1;0 and 2;0 and their caregivers were recorded in two contexts: joint bookreading and play with toys. Context had the largest effect, as nouns were much more frequent in the book context. Noun dominance was constant across development in the book context, but in the toy context there was a shift away as children developed from single words through the presyntactic stage to the syntactic stage. Caregiver language was verb dominant in a number of respects across development in the toy context, and thus was not closely related to child lexical balance. We conclude that in early lexical development, all children have a conceptual disposition to learn nouns. With vocabulary growth and the emergence of grammar, the proportion of verbs increases substantially, and at this stage properties of the input language may influence development.

Overgeneralization occurs when a child uses the wrong word to name an object and is often observed in the early stages of word learning. We develop a method to elicit overgeneralizations in the laboratory by priming children to say the names of objects perceptually similar to known and unknown target objects. Experiment 1 examined 18 two-year-old children's labelling of familiar and unfamiliar objects, using a name that was previously produced. Experiment 2 compared the labelling of 30 two-year-olds and 39 four-year-olds when presented with completely novel objects. The findings suggest that the retrieved word is a blend of previous activation from the prior retrieval and activation engendered by the similarity of the test object to instances of the target category. We put forward a theoretical account of overgeneralization based on current models of adult language processing. The account suggests a common mechanism of activation and retrieval, which may explain not only momentary lapses in the correct selection of words, but other types of naming errors traditionally thought to reflect differences in children's underlying category representations or, perhaps, gaps in their knowledge of words.

We hypothesize that the conceptual relation between a verb and its direct object can make a sentence easier (‘the cat is eating some food’) or harder (‘the cat is eating a sock’) to parse and understand. If children's limited performance systems contribute to the ungrammatical brevity of their speech, they should perform better on sentences that require fewer processing resources: children should imitate the constituents of sentences with highly predictable direct objects at a higher rate than those from sentences with less predictable objects. In Experiment 1, 24 two-year-olds performed an elicited imitation task and confirmed that prediction for all three major constituents (subject, verb, direct object). In Experiment 2, 23 two-year-olds performed both an elicited imitation task and a sticker placement task (in which they placed a sticker on the pictured subject of the sentence after hearing and imitating the sentence). Children imitated verbs more often from predictable than unpredictable sentences, but not subjects or objects. Children's inclusion of constituents is affected by the conceptual relations among those constituents as well as by task characteristics.

Phonological representation for adult speakers is generally assumed to include sub-lexical information at the level of the phoneme. Some have suggested, however, that young children operate with more holistic lexical representations. If young children use whole-word representation and adults employ phonemic representation, then a component of phonological development includes a transition from holistic to segmental storage of phonological information. The present study addresses the nature of this transition by investigating the prevalence and patterns of intra-word production variability during the first year of lexical acquisition (1;0–2;0). Longitudinal data from four typically developing children were analysed to determine variability at each age. Patterns of variability are discussed in relation to chronological age and productive vocabulary size. Results show high overall rates of variability, as well as a peak in variability corresponding to the onset of combinatorial speech, suggesting that phonological reorganization may commence somewhat later than previously thought.

The acquisition of German plurals has been the focus of controversy in the last decade. In this paper we claim that degree of productivity (i.e. the capacity of nouns to form potential plurals) plays a key role in determining pace of acquisition. A plural elicitation task was administered to 84 Viennese German-speaking children aged 2;6 to 6;0. Analyses of correct responses showed that the highest scores were obtained with -e plurals, followed by the plural markers -e +U, -er +U, -s and -(e)n. The lowest score was observed for pure Umlaut (U) plurals. Analyses suggested an impact of productivity on the number of correct scores: fully productive and productive plural patterns obtained higher correct scores than weakly productive and non-productive ones. The results of the study support our productivity scale and are compatible both with single-route models and with a race-model variant of the dual-route view.

This paper presents a model of syntax acquisition, whose main points are as follows: Syntax is acquired in an item-based manner; early learning facilitates subsequent learning – as evidenced by the accelerating rate of new verbs entering a given structure; and mastery of syntactic knowledge is typically achieved through practice – as evidenced by intensive use and common word order errors – and this slows down learning during the early stages of acquiring a structure.

The facilitation and practice hypotheses were tested on naturalistic production samples of six Hebrew-acquiring children ranging from ages 1;1 to 2;7 (average ages 1;6 to 2;4 months). Results show that most structures did in fact accelerate; the notion of ‘practice’ is supported by the inverse correlation found between number of verbs and number of errors in the earliest productions in a given structure; and the absence of acceleration in a minority of the structures is due to the fact that they involve relatively less practice.

One of the tasks of language learning is the discovery of the intricate division of labour between the lexical-semantic content of an expression and the pragmatic inferences the expression can be used to convey. Here we investigate experimentally the development of the semantics–pragmatics interface, focusing on Greek-speaking five-year-olds' interpretation of aspectual expressions such as arxizo (‘start’) and degree modifiers such as miso (‘half’) and mexri ti mesi (‘halfway’). Such expressions are known to give rise to scalar inferences crosslinguistically: for instance, start, even though compatible with expressions denoting completion (e.g. finish), is typically taken to implicate non-completion. Overall, our experiments reveal that children have limited success in deriving scalar implicatures from the use of aspectual verbs but they succeed with ‘discrete’ degree modifiers such as ‘half’. Furthermore, children are better at spontaneously computing scalar implicatures than judging the pragmatic appropriateness of scalar statements. Finally, children can suspend scalar implicatures in environments where they are not supported. We discuss implications of these results for the scope and limitations of children's ability to both acquire the lexical semantics of aspectuals and to compute implicatures as part of what the speaker means.

Forty Polish children aged between 1;8 and 2;3 were trained over two training sessions in the comprehension of the preposition POD [UNDER]. In the experiment, two variables were manipulated: a within subjects variable of SITUATION and a between subjects variable of LINGUISTIC INPUT. The effect of situation could be found in all trained groups, showing that children's understanding in familiar and transfer situations differed significantly from the performance of the control group in the post-test. The results further suggest that depending on the type of a situation, the linguistic task requires different word learning abilities from a child.

Pragmatic development requires the ability to use linguistic forms, along with non-verbal cues, to focus an interlocutor's attention on a referent during conversation. We investigate the development of this ability by examining how the use of demonstratives is learned in Turkish, where a three-way demonstrative system (bu, şu, o) obligatorily encodes both distance contrasts (i.e. proximal and distal) and absence or presence of the addressee's visual attention on the referent. A comparison of the demonstrative use by Turkish children (6 four- and 6 six-year-olds) and 6 adults during conversation shows that adultlike use of attention directing demonstrative, şu, is not mastered even at the age of six, while the distance contrasts are learned earlier. This language specific development reveals that designing referential forms in consideration of recipient's attentional status during conversation is a pragmatic feat that takes more than six years to develop.

Variations in the amount and nature of early language to which children are exposed have been linked to their subsequent ability (e.g. Huttenlocher, Haight, Bryk, Seltzer & Lyons, 1991; Hart & Risley, 1995). In three computational simulations, we explore how differences in linguistic experience can explain differences in word learning ability due to changes in the development of semantic category structure. More specifically, we manipulate the amount of language input, sentential complexity, and the frequency distribution of words within categories. In each of these simulations, improvements in category structure, are tightly correlated with subsequent improvements in word learning ability even when the nature of the input remains the same over time. These simulations suggest that variation in early language environments may result in differences in lexical proficiency by altering underlying cognitive abilities like categorization.

This study investigated different accounts of children's acquisition of non-subject wh-questions. Questions using each of 4 wh-words (what, who, how and why), and 3 auxiliaries (BE, DO and CAN) in 3sg and 3pl form were elicited from 28 children aged 3;6–4;6. Rates of non-inversion error (Who she is hitting?) were found not to differ by wh-word, auxiliary or number alone, but by lexical auxiliary subtype and by wh-word+lexical auxiliary combination. This finding counts against simple rule-based accounts of question acquisition that include no role for the lexical subtype of the auxiliary, and suggests that children may initially acquire wh-word+lexical auxiliary combinations from the input. For DO questions, auxiliary-doubling errors (What does she does like?) were also observed, although previous research has found that such errors are virtually non-existent for positive questions. Possible reasons for this discrepancy are discussed.

57 Polish-speaking children aged from 2;4, to 4;8 and 16 adult controls participated in a nonce-word inflection experiment testing their ability to use the genitive, dative and accusative inflections productively. Results show that this ability develops early: the majority of two-year-olds were already productive with all inflections apart from dative neuter; and the overall performance of the four-year-olds was very similar to that of adults. All age groups were more productive with inflections that apply to large and/or phonologically diverse classes, although class size and token frequency appeared to be more important for younger children (two- and three-year-olds) and phonological diversity for older children and adults. Regularity, on the other hand, was a very poor predictor of productivity. The results support usage-based models of language acquisition and are problematic for the dual mechanism model.

Some authors have suggested that definitional skills include metalinguistic components (Watson, 1985; Snow, 1990; McGhee-Bidlack, 1991). The present study therefore empirically investigated relations between the ability to define words and level of metalinguistic awareness in 280 Italian children (with ages ranging from 5 to 11 years) and in two groups of 40 adults each (with low and high educational levels, respectively). We used a definitional task presenting 24 terms (nouns, verbs, and adjectives, which were either concrete or abstract) and a task examining 6 different aspects of metalinguistic awareness. Our aim was to demonstrate that metalinguistic skills can positively predict the formal quality of definitions and to identify various aspects of metalinguistic skills that might be directly related to definitional skills. Results showed better performance on both tasks as a function of age and educational level; they also confirmed the important roles of metalinguistic ability and educational level in producing well-structured formal definitions.

The study investigates a social–pragmatic expectation that may motivate children to search their environment when asked for the referent of a novel label. In one experimental phase, the experimenter presented 40 two-year-olds a bucket containing a novel object and another visible object – either familiar or novel. The experimenter either asked children for the referent of a novel label, or a non-specific question. In a second experimental phase, all children saw a bucket containing a novel object, and two visible objects – one familiar and one novel. We found that, in both phases, children tended to bypass the visible novel object, preferring instead to search inside the bucket for the referent of a novel label. These findings are consistent with an expectation – dubbed the EXPECTATION OF COMPETENCE – that if an adult asks a child for the referent of a name, it is because the adult likely believes that the child knows that name, and thus the child can expect to be capable of finding its referent.

The paper examines the nominal lexicon in later language acquisition as a window on linguistic knowledge and usage across childhood and adolescence. The paper presents a psycholinguistically motivated and cognitively grounded analysis of the distribution of ten semantic noun categories (the Noun Scale) across development, modality, and genre. Eighty Hebrew-speaking children (9;0 to 10;0), adolescents (12;0 to 13;0 and 16;0 to 17;0), and a group of adult university graduate students participated in the study. Each produced four different texts: a spoken and written narrative and a spoken and written expository, yielding a total of 320 texts. All lexical noun tokens in each of the 320 texts were analysed to determine their score on the Noun Scale. Results indicate that nominal density, which underlies much of the syntactic architecture of texts, increases dramatically in adolescence, towards adulthood. The paper analyses the developmental patterns of each of the ten Noun Scale categories, showing that the nominal lexicon of schoolaged children is already very different from that of young children in having only a small amount of genuinely concrete nouns, and these too only in narrative texts. The quantitative analysis shows that nouns grow more categorical and abstract with age and schooling, especially in adolescence. Written expository texts are the preferred habitat of abstract, categorical nouns from early on. The systematic qualitative analysis of noun tokens in their textual context demonstrates how the nominal lexicon undergoes fundamental changes that are affected by linguistic, cognitive and social development, in interaction with text genre and modality.