The effect of perceptual availability and prior discourse on young children's use of referring expressions.

Choosing appropriate referring expressions requires assessing whether a referent is “available” to the addressee either perceptually or through discourse. In Study 1, we found that 3- and 4-year-olds, but not 2-year-olds, chose different referring expressions (noun vs. pronoun) depending on whether their addressee could see the intended referent or not. In Study 2, in more neutral discourse contexts than previous studies, we found that 3- and 4-year-olds clearly differed in their use of referring expressions according to whether their addressee had already mentioned a referent. Moreover, 2-yearolds responded with more naming constructions when the referent had not been mentioned previously. This suggests that, despite early social–cognitive developments, (a) it takes time tomaster the given/new contrast linguistically, and (b) children understand the contrast earlier based on discourse, rather than perceptual context

Converging and competing cues in the acquisition of syntactic structures: The conjoined agent intransitive

ABSTRACTIn two studies we use a pointing task to explore developmentally the nature of the knowledge that underlies three- and four-year-old children's ability to assign meaning to the intransitive structure. The results suggest that early in development children are sensitive to a first-noun-as-causal-agent cue and animacy cues when interpreting conjoined agent intransitives. The same children, however, do not appear to rely exclusively on the number of nouns as a cue to structure meaning. The pattern of results indicates that children are processing a number of cues when inferring the meaning of the conjoined agent intransitive. These cues appear to be in competition with each other and the cue that receives the most activation is used to infer the meaning of the construction. Critically, these studies suggest that children's knowledge of syntactic structures forms a network of organization, such that knowledge of one structure can impact on interpretation of other structures.</jats:p

The acquisition of questions with long-distance dependencies

A number of researchers have claimed that questions and other constructions with long distance dependencies (LDDs) are acquired relatively early, by age 4 or even earlier, in spite of their complexity. Analysis of LDD questions in the input available to children suggests that they are extremely stereotypical, raising the possibility that children learn lexically specific templates such as WH do you think S-GAP? rather than general rules of the kind postulated in traditional linguistic accounts of this construction. We describe three elicited imitation experiments with children aged from 4;6 to 6;9 and adult controls. Participants were asked to repeat prototypical questions (i.e., questions which match the hypothesised template), unprototypical questions (which depart from it in several respects) and declarative counterparts of both types of interrogative sentences. The children performed significantly better on the prototypical variants of both constructions, even when both variants contained exactly the same lexical material, while adults showed prototypicality e¤ects for LDD questions only. These results suggest that a general declarative complementation construction emerges quite late in development (after age 6), and that even adults rely on lexically specific templates for LDD questions

Geographic Information System mapping of snakebite incidence in northern Ghana and Nigeria using environmental indicators: a preliminary study.

Snakebite is an important health problem in many parts of rural West Africa where the carpet or sawscaled viper, Echis ocellatus, is responsible for most of the morbidity and mortality. Marked seasonal and geographical variation in the incidence of snakebite suggests an association with environmental factors that could potentially identify high-risk areas and inform health care decision making. This preliminary investigation describes a Geographic Information System (GIS) approach to risk mapping that identifies environmental variables potentially associated with variation in snakebite incidence rates at a number of health facilities in northern Ghana and Nigeria and which has been used to create a preliminary risk map of the potential probability of high snakebite incidence for West Africa. Detailed and extensive further studies will enable the more reliable estimation of snakebite incidence at a local level across the region

Structural and interactional aspects of adverbial sentences in English mother-child interactions:an analysis of two dense corpora

We analysed both structural and functional aspects of sentences containing the four adverbials “after”, “before”, “because”, and “if” in two dense corpora of parent-child interactions from two British English-acquiring children (2;00–4;07). In comparing mothers’ and children's usage we separate out the effects of frequency, cognitive complexity and pragmatics in explaining the course of acquisition of adverbial sentences. We also compare these usage patterns to stimuli used in a range of experimental studies and show how differences may account for some of the difficulties that children have shown in experiments. In addition, we report descriptive data on various aspects of adverbial sentences that have not yet been studied as a resource for future investigations

The acquisition of English modal constructions:A corpus-based analysis

The English modal system is complex, exhibiting many-to-one, and one-to-many, form- function mappings. Usage-based approaches emphasise the role of the input in acquisition but rarely address the impact of form-function mappings on acquisition. To test whether consistent form-function mappings facilitate acquisition, we analysed two dense mother-child corpora at age 3 and 4. We examined the influence on acquisition of input features including form-function mapping frequency and the number of functions a modal signifies, using innovative methodological controls for other aspects of the input (e.g. form frequency) and child characteristics (e.g. age as a proxy for socio-cognitive development). The children were more likely to produce the frequent modals and form-function mappings of their input but modals with fewer functions in caregiver speech did not promote acquisition of these forms. Our findings support usage-based approaches to language acquisition and demonstrate the importance of applying appropriate controls when investigating relationships between input and development