a1 University of Reading
a2 University of Bristol
A recurring result from studies which relate the frequency of input variables to rate of language development, is the link between auxiliary verb growth and yes—no questions addressed to children. Explanations for this relationship usually concentrate on the advantages of hearing stressed and non-contracted auxiliary forms in sentence-initial position over hearing unstressed, contracted forms in medial position in declaratives. If such accounts are correct, then it can be predicted that yes—no questions which place forms of COPULA be in initial position will also increase the rate of growth of children's COPULA verb development. This prediction was tested using a sample of 33 children, carefully matched for stage of language development at 1;9 and 2;0 years; rate of copula verb growth was then measured over the succeeding nine months. Analyses include an examination of the contribution of sub-categories of yes—no question, tag questions, and utterances containing sentence-final copulas to the growth of contracted and full copulas. Results confirm that the frequency of inverted copulas in yes—no questions predicts children's copula development. Nevertheless, caution is urged before interpreting the relationship in terms of a direct causal model.
(Received April 29 1991)
(Revised April 14 1992)
c1 Address for correspondence: Department of Arts and Humanities in Education, University of Reading, Bulmershe Court, Earley, Readine, RG6 1HY, UK.
[*] This article is based on research carried out as part of the project ‘Environmental predictors of auxiliary and copula verb growth in young children’, funded by the Economic and Social Research Council (ESRC), reference number: RC00232471. We would like to thank the following: Lynette Dunn and Mair Richards for their assistance with the coding and analysis of the data; Sally Barnes for some helpful discussions on the statistical analysis; Mina Drever, Annette Karmiloff-Smith, Mair Richards and two anonymous reviewers for their comments on previous versions. Selected preliminary results from this study were presented at the Child Language Seminar, University of Kent at Canterbury, 1990.