The Editors would like to register their great sadness at the tragically early death of our colleague, Elizabeth Bates. The loss of her empirical breadth, her theoretical engagement and her sheer energy and enthusiasm for the fundamental questions that engage us all, will leave a huge gap.

The acquisition of case and gender marking on the definite and indefinite article was studied in a sample of 6 normally-hearing children and 9 children with cochlear implants. Longitudinal spontaneous speech data are used. Children were matched by MLU, with 4 MLU levels: 1·8, 2·8, 3·6, 4·8. Age ranges for normally-hearing children were 1;4 to 3;8 and for children with cochlear implants 1;8 to 7;0. Frequencies of correctly marked article forms increased over MLU but less so in the hearing-impaired group. In both groups error rates were high. However, error patterns were different. In normally-hearing children errors of case predominated, in hearing-impaired children errors of gender and omission. Error patterns suggest that in normally-hearing children syntactic categorization interacts with input frequency and low discriminability of article forms. In the hearing-impaired group the article system is less advanced, despite higher frequencies of definite articles in adult speech. The predominance of article omission is discussed in terms of persisting perceptual problems or a working memory deficit.

The purpose of this research was to show how the syntactic and semantic components of the tense–aspect system interact during the acquisition process. Our methodology involved: (1) identifying predicates, (2) finding the initial occurrence of their tense–aspect morphology, and (3) observing the emergence of contrasts. Six children learning Polish and six children learning English, found in the CHILDES archives, were investigated. The average starting age of the children learning English was 1;11, and 1;8 for the children learning Polish. In the first analysis, we traced the same 12 verbs in both languages, and in the second analysis, we contrasted the acquisition patterns for a set of telic versus atelic predicates. We tracked the verbs/predicates from the starting age to 4;11 or the child's final transcript. In English, progressive aspect is the marked form, and in Polish, perfective aspect is the marked form. This typological distinction has a significant effect of the acquisition patterns in the two languages. We argue that children acquire a multi-dimensional system having deictic relations as one of the basic dimensions. This process can be best understood within a functional theoretical framework having a well-defined syntactic–semantic interface.

In many areas of language acquisition, researchers have suggested that semantic generality plays an important role in determining the order of acquisition of particular lexical forms. However, generality is typically confounded with the effects of input frequency and it is therefore unclear to what extent semantic generality or input frequency determines the early acquisition of particular lexical items. The present study evaluates the relative influence of semantic status and properties of the input on the acquisition of verbs and their argument structures in the early speech of 9 English-speaking children from 2;0 to 3;0. The children's early verb utterances are examined with respect to (1) the order of acquisition of particular verbs in three different constructions, (2) the syntactic diversity of use of individual verbs, (3) the relative proportional use of semantically general verbs as a function of total verb use, and (4) their grammatical accuracy. The data suggest that although measures of semantic generality correlate with various measures of early verb use, once the effects of verb use in the input are removed, semantic generality is not a significant predictor of early verb use. The implications of these results for semantic-based theories of verb argument structure acquisition are discussed.

There has been relatively little discussion in the field of child language acquisition about how best to sample from children's spontaneous speech, particularly with regard to quantitative issues. Here we provide quantitative information designed to help researchers make decisions about how best to sample children's speech for particular research questions (and/or how confident to be in existing analyses). We report theoretical analyses in which the major parameters are: (1) the frequency with which a phenomenon occurs in the real world, and (2) the temporal density with which a researcher samples the child's speech. We look at the influence of these two parameters in using spontaneous speech samples to estimate such things as: (a) the percentage of the real phenomenon actually captured, (b) the probability of capturing at least one target in any given sample, (c) the confidence we can have in estimating the frequency of occurrence of a target from a given sample, and (d) the estimated age of emergence of a target structure. In addition, we also report two empirical analyses of relatively infrequent child language phenomena, in which we sample in different ways from a relatively dense corpus (two children aged 2;0 to 3;0) and compare the different results obtained. Implications of these results for various issues in the study of child language acquisition are discussed.

In two eye-tracking experiments, we investigate adults' and children's on-line processing of referentially ambiguous English pronouns. Sixteen adults and 16 four-to-seven-year-olds listened to sentences with either an unambiguous reflexive (himself) or an ambiguous pronoun (him) and chose a picture with two characters that corresponded to those in the sentence. For adults, behavioural data, responses and reaction times indicate that pronouns are referentially ambiguous. Adults' eye movements show a competition between the looks to sentence-internal and -external referents for pronouns, but not for reflexives. Children overwhelmingly prefer the sentence-internal referent in the off-line picture selection task. However, their eye movements reveal implicit awareness of referential ambiguity that develops earlier than their explicit knowledge in the picture selection task. This discrepancy between performance on a looking measure and a pointing measure in the children's processing system is explained by a general dissociation between implicit and explicit knowledge proposed in recent literature on cognitive development.

The effect of both geometric and extra-geometric factors on children's production of in is reported (free-response paradigm). Eighty children across four age groups (means 4;1, 5;5, 6;1, and 7;1) were shown video scenes of puppets placing real objects in various positions with reference to a bowl and a plate. Located objects were placed at three heights on top of piles of other objects in the scene. The extra-geometric factor of location control of the located object was manipulated by comparing static scenes to dynamic scenes in which the located object was depicted as either moving independently of, or together with, the reference object. Additionally, the located object was placed on other objects that were either the same or different (e.g. an apple on apples or on oranges). The results indicate that even the youngest children altered the way they talked according to not only geometric but also extra-geometric factors.

Recent studies have suggested that cultures vary in subtle ways in the talk about talk that children hear and learn to produce. Twenty-two three-year-old children and their families in respectively Oslo, Norway and Cambridge, Massachusetts were observed during mealtime with the aim of identifying talk-focused talk. The analysis distinguished talk about (a) language per se, (b) discourse management, and (c) former conversations and use of reported speech. No category of talk-focused talk appeared exclusively in either community, and the frequency of such talk was similar across these. The Oslo families talked more often about language per se and their talk-focused conversations typically had a question–answer form. Talk about talk appeared more often within narratives in Oslo and within explanations in Cambridge. A second analysis compared talk-focused talk at home with such talk at school, suggesting that talk about language per se appeared more often at school across the two communities.

Mazzocco (1997) claimed that children have persistent difficulty in learning pseudo-homonyms – words like rope used to refer to a novel object (e.g. spade). Because the novel objects were familiar, the pseudo-homonyms in her study were also synonyms (i.e. rope and spade both now mean spade). The results could therefore be due to children's well-known difficulties in learning synonyms. In Experiment 1, 55 six- to ten-year-olds used story context to select referents for pseudo-homonyms from picture sets containing the intended referents, with primary referents amongst the distractors. Children were equally poor when the intended referents were familiar (e.g. spade) as when they were unfamiliar (e.g. tapir) – 35 and 38% correct, respectively. This indicates that familiarity of referent does not account for children's difficulties. In Experiment 2, 64 five- to ten-year-olds received instruction about homonymy, then a story set without pictures of the primary referents, in order to make the experimenter's intentions clear. Children were then shown one of the story sets from Experiment 1. Performance was just as poor (38% correct), indicating that misunderstanding of task demands did not account for failure. The conclusion is that Mazzocco's findings represent a psychologically interesting developmental difficulty.

This study aimed to clarify the development of conversational style in Japanese mother–child interactions. We focused on the frequency of speech overlap as an index of Japanese conversational style, with particular attention to ne, a particle produced by the speaker, and to backchannels, such as ‘uh-huh’, produced by the listener that support sympathetic conversation. The results of longitudinal observations of two Japanese mother–child dyads from approximately 0;11 to 3;3 suggest that an adultlike conversational style with frequent overlaps emerges in Japanese child-directed speech around the two-word utterance period, and a child's development of ne use is closely related to this shift.

According to the AGREEMENT/TENSE (Agr/Tns) OMISSION MODEL, children's failure to produce finite verb morphemes represents the selection of an optional infinitive form, in which tense and/or agreement is not specified. When agreement is specified, nominative case is licensed. Following the assumptions of this model, a child's utterance such as She run reflects a failure to specify tense only, given that the subject pronoun shows nominative case. We tested this assumption in two studies through the analysis of spontaneous speech samples from young typically-developing (TD) children and children with specific language impairment (SLI). In Study 1, 15 children were included (TD aged 2;1–3;11, SLI aged 4;0–6;2); in Study 2, 33 children were included (TD aged 2;5–3;11, SLI aged 3;6–6;9). We determined whether there was a relationship between the children's use of past tense -ed and their use of third person singular -s and copula is when nominative case was also used. Because nominative case was used, any failures to produce third person singular -s and copula is should be attributable to tense and not agreement. Such use should therefore be related to the children's use of -ed which presumably hinges on tense only. However, a relationship was not found in the speech of either group of children. This was true both for the children in each group who were consistent in using nominative case pronouns and for those who were not. Possible reasons for these findings are discussed.