Publications

Abstract

Introduction

Children's early language and communication skills are efficiently measured using parent report, for example, communicative development inventories (CDIs). These have scalable potential to determine risk of later language delay, and associations between delay and risk factors such as prematurity and poverty. However, there may be measurement difficulties in parent reports, including anomalous directions of association between child age/socioeconomic status and reported language. Findings vary on whether parents may report older infants as having smaller vocabularies than younger infants, for example.

Methods

We analysed data from the UK Communicative Development Inventory (Words and Gestures); UK-CDI (W&G) to determine whether anomalous associations would be replicated in this population, and/or with gesture. In total 1204 families of children aged 8–18 months (598 girls, matched to UK population for income, parental education and ethnicity as far as possible) completed Vocabulary and Gesture scales of the UK-CDI (W&G).

Results

Overall scores on the Gesture scale showed more significant relationships with biological risk factors including prematurity than did Vocabulary scores. Gesture also showed more straightforward relationships with social risk factors including income. Relationships between vocabulary and social risk factors were less straightforward; some at-risk groups reported higher vocabulary scores than other groups.

Discussion

We conclude that vocabulary report may be less accurate than gesture for this age. Parents have greater knowledge of language than gesture milestones, hence may report expectations for vocabulary, not observed vocabulary. We also conclude that gesture should be included in early language scales partly because of its greater, more straightforward association with many risk factors for language delay.

Abstract

A long-standing question in language development concerns the nature of the relationship between early lexical and grammatical knowledge. The very strong correlation between the two has led some to argue that lexical and grammatical knowledge may be inseparable, consistent with psycholinguistic theories that eschew a distinction between the two systems. However, little research has explicitly examined whether early lexical and grammatical knowledge are statistically separable. Moreover, there are two under-appreciated methodological challenges in such research. First, the relationship between lexical and grammatical knowledge may change during development. Second, non-linear mappings between true and observed scores on scales of lexical and grammatical knowledge could lead to spurious multidimensionality. In the present study, we overcome these challenges by using vocabulary and grammar data from several developmental time points and a statistical method robust to such non-linear mappings. In Study 1, we examined item-level vocabulary and grammar data from two American English samples from a large online repository of data from studies employing a commonly used language development scale. We found clear evidence that vocabulary and grammar were separable by two years of age. In Study 2, we combined data from two longitudinal studies of language acquisition that used the same scale (at 18/19, 21, 24 and 30 months) and found evidence that vocabulary and grammar were, under some conditions, separable by 18 months. Results indicate that, while there is clearly a very strong relationship between vocabulary and grammar knowledge in early language development, the two are separable. Implications for the mechanisms underlying language development are discussed.

Abstract

Preschoolers’ exposure to abstract language (i.e. talk beyond the here and now) during shared reading is associated with language development. This randomized intervention study tested whether preschoolers’ repeated exposure to simple and complex stories (as defined by the inferential demands of the story), and the extratextual talk associated with such stories, would lead to differences in language production during shared reading and to differential gains in vocabulary and narrative skills post intervention. An experimenter read scripted stories to 34 children (3;07–4;11) assigned to one of two story conditions (simple or complex) in small-groups, twice weekly over six weeks. Results showed that children in the complex story condition produced more complex language (as indexed by their mean length of utterance, use of mental and communication verbs, and use of subordinate clauses). However, post-intervention, children’s vocabulary and narrative skills did not differ between conditions. Specific kinds of stories and corresponding extratextual talk by adults may not only increase children’s exposure to rich and challenging input from the extratextual talk, but can also provide valuable opportunities for children to produce complex language. Theoretical and methodological implications are also discussed.

Abstract

According to Crain and Nakayama (1987), when forming complex yes/no questions, children do not make errors such as Is the boy who smoking is crazy? because they have innate knowledge of structure dependence and so will not move the auxiliary from the relative clause. However, simple recurrent networks are also able to avoid such errors, on the basis of surface distributional properties of the input (Lewis & Elman, 2001; Reali & Christiansen, 2005). Two new elicited production studies revealed that (a) children occasionally produce structure-dependence errors and (b) the pattern of children's auxiliary-doubling errors (Is the boy who is smoking is crazy?) suggests a sensitivity to surface co-occurrence patterns in the input. This article concludes that current data do not provide any support for the claim that structure dependence is an innate constraint, and that it is possible that children form a structure-dependent grammar on the basis of exposure to input that exhibits this property.

Abstract

Participants (aged 5–6 yrs, 9–10 yrs and adults) rated (using a five-point scale) grammatical (intransitive) and overgeneralized (transitive causative)1 uses of a high frequency, low frequency and novel intransitive verb from each of three semantic classes [Pinker, S. (1989a). Learnability and cognition: the acquisition of argument structure. Cambridge, MA: MIT Press]: “directed motion” (fall, tumble), “going out of existence” (disappear, vanish) and “semivoluntary expression of emotion” (laugh, giggle). In support of Pinker’s semantic verb class hypothesis, participants’ preference for grammatical over overgeneralized uses of novel (and English) verbs increased between 5–6 yrs and 9–10 yrs, and was greatest for the latter class, which is associated with the lowest degree of direct external causation (the prototypical meaning of the transitive causative construction). In support of Braine and Brooks’s [Braine, M.D.S., & Brooks, P.J. (1995). Verb argument strucure and the problem of avoiding an overgeneral grammar. In M. Tomasello & W. E. Merriman (Eds.), Beyond names for things: Young children’s acquisition of verbs (pp. 352–376). Hillsdale, NJ: Erlbaum] entrenchment hypothesis, all participants showed the greatest preference for grammatical over ungrammatical uses of high frequency verbs, with this preference smaller for low frequency verbs, and smaller again for novel verbs. We conclude that both the formation of semantic verb classes and entrenchment play a role in children’s retreat from argument-structure overgeneralization errors.

Abstract

One of the most influential recent accounts of pronoun case-marking errors in young children's speech is Schütze & Wexler's (1996) Agreement/Tense Omission Model (ATOM). The ATOM predicts that the rate of agreeing verbs with non-nominative subjects will be so low that such errors can be reasonably disregarded as noise in the data. The present study tests this prediction on data from 12 children between the ages of 1;8.22 and 3;0.10. This is done, first, by identifying children who produced a reasonably large number of non-nominative 3psg subjects; second, by estimating the expected rate of agreeing verbs with masculine and feminine non-nominative subjects in these children's speech; and, third, by examining the actual rate at which agreeing verb forms occurred with non-nominative subjects in those areas of the data in which the expected error rate was significantly greater than 10%. The results show, first, that only three of the children produced enough non-nominative subjects to allow a reasonable test of the ATOM to be made; second, that for all three of these children, the only area of the data in which the expected frequency of agreeing verbs with non-nominative subjects was significantly greater than 10% was their use of feminine case-marked subjects; and third, that for all three of these children, the rate of agreeing verbs with non-nominative feminine subjects was over 30%. These results raise serious doubts about the claim that children's use of non-nominative subjects can be explained in terms of AGR optionality, and suggest the need for a model of pronoun case-marking error that can explain why some children produce agreeing verb forms with non-nominative subjects as often as they do.

Abstract

Many current generativist theorists suggest that young children possess the grammatical principles of inversion required for question formation but make errors because they find it difficult to learn language-specific rules about how inversion applies. The present study analyzed longitudinal spontaneous sampled data from twelve 2–3-year-old English speaking children and the intensive diary data of 1 child (age 2;7 [years;months] to 2;11) in order to test some of these theories. The results indicated significantly different rates of error use across different auxiliaries. In particular, error rates differed across 2 forms of the same auxiliary subtype (e.g., auxiliary is vs. are), and auxiliary DO and modal auxiliaries attracted significantly higher rates of errors of inversion than other auxiliaries. The authors concluded that current generativist theories might have problems explaining the patterning of errors seen in children's questions, which might be more consistent with a constructivist account of development. However, constructivists need to devise more precise predictions in order to fully explain the acquisition of questions.

Abstract

This study examined patterns of auxiliary provision and omission for the auxiliaries BE and HAVE in a longitudinal data set from 11 children between the ages of two and three years. Four possible explanations for auxiliary omission—a lack of lexical knowledge, performance limitations in production, the Optional Infinitive hypothesis, and patterns of auxiliary use in the input—were examined. The data suggest that although none of these accounts provides a full explanation for the pattern of auxiliary use and nonuse observed in children's early speech, integrating input-based and lexical learning-based accounts of early language acquisition within a constructivist approach appears to provide a possible framework in which to understand the patterns of auxiliary use found in the children's speech. The implications of these findings for models of children's early language acquisition are discussed.