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.

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.

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.

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.

We examined children's use of apology terms in parent–child discourse. Longitudinal data from 9 children (5 males, 4 females) between the ages of 1;2 and 6;1 were analysed. Before 2;0, the use of apology terms was rare. Thereafter, several developmental trends were noted including a decrease with age in directly elicited apologies and an increase in indirectly elicited apologies. With age children's apologies also became more elaborate. Children were exposed to apology terms primarily through apologies directed to them and, to a lesser degree, in talk about apologies. Our study documents young children's early mastery of an important pragmatic skill and identifies parents' role in its acquisition.

This study investigates the role of phonological and morphological information in children's developing orthographies in two languages with different linguistic typologies: Hebrew, a Semitic language with a highly synthetic morphology, and Dutch, a Germanic language with a sparse morphology.

192 Israeli and 192 Belgian monolingual schoolchildren in grades 1–6 (aged 6;0–12;0) were administered respective dictation tasks in which homophonous segments were the targets. In each language, these phonologically distinct segments are neutralized phonetically but are nevertheless represented orthographically. In both languages the target segments in the test words differed along two dimensions: (1) their morphological function as part of a stem or root versus as part of an affix; and (2) their morphophonological recoverability. The spelling tests in both languages consisted of four conditions which differed in the number and type of cues for retrieving the correct spelling of homophonous graphemes. The cues were of two types: morphological cues, which offer spellers clues to the correct spelling through consistent orthography/morphology mapping regularities; and morphophonological cues, which offer spellers clues to the correct spelling through the manipulation of orthography/morphophonology conversion procedures.

A central finding of this study is the differential treatment of morphological cues by Dutch and Hebrew spelling learners. When faced with neutralized segments with and without morphological function, Hebrew-speaking children find morphology an enormously helpful tool. Dutch-speaking children, in contrast, do not find morphology a good cue provider. The impact of typology on the interface between spoken and written language is invoked as an explanation of the main findings.

Modifications mothers make when talking to young English-speaking children between the ages of 1;8 and 3;0 (average age=2;4) about words perceived to be familiar versus unfamiliar were investigated. Nineteen mothers and their children participated in two toy play tasks; one designed to elicit talk about familiar and unfamiliar animals and the other designed to elicit talk about familiar and unfamiliar actions. It was found that mothers' talk involving unfamiliar words differed from talk involving familiar words in a number of ways. Some modifications served to highlight the unfamiliar word which could assist in segmenting the unfamiliar word and mapping it to its referent. Compared to familiar nouns and verbs, unfamiliar nouns and verbs were produced more frequently in highly salient utterance positions and were paired more consistently with a clear nonverbal referent. Familiar nouns but, not verbs, were produced in longer utterances than unfamiliar nouns which could support the child's elaboration of the lexical representation of the familiar word.

Over the course of acquiring deverbal compounds like truck driver, English-speaking children pass through a stage when they produce ungrammatical compounds like drive-truck. These errors have been attributed to canonical phrasal ordering (Clark, Hecht & Mulford, 1986). In this study, we compared British and Canadian children's compound production. Both dialects have the same phrasal ordering but some different lexical items (e.g. answer-phone exists only in British English). If influenced by these lexical differences, British children would produce more ungrammatical Verb–Object (VO) compounds in trying to produce the more complex deverbal (Object–Verb-er) than the Canadian children. 36 British children between the ages of 3;6 and 5;6 and 36 age-matched Canadian children were asked to produce novel compounds (like sun juggler). The British children produced more ungrammatical compounds and fewer grammatical compounds than the Canadian children. We argue that children's errors in deverbal compounds may be due in part to competing lexical structures.