Vocabulary richness, including lexical diversity and use of rare words, has an important role in assessing proficiency, diagnosing progress and testing theory in the study of language development. This book first reviews different methods for quantifying how vocabulary is deployed in spontaneous speech and writing, and then introduces an alternative approach which can assess overall lexical diversity, measure morphology development and compare the development of different word classes. The new approach is illustrated by its application to first and second language learners.

Vocabulary richness, including lexical diversity and use of rare words, has an important role in assessing proficiency, diagnosing progress and testing theory in the study of language development. This book first reviews different methods for quantifying how vocabulary is deployed in spontaneous speech and writing, and then introduces an alternative approach which can assess overall lexical diversity, measure morphology development and compare the development of different word classes. The new approach is illustrated by its application to first and second language learners.

Is native speaker variation in understanding complex sentences due to individual differences in working memory capacity or in syntactic competence? The answer to this question has very important consequences for both theoretical and applied concerns in linguistics and education. This book is distinctive in giving an historical and interdisciplinary perspective on the rule- based and experience-based debate and in supporting an integrated account. In the study reported here, variation was found to be due to differences in syntactic competence and the author argues that sentence comprehension is a learned skill, displaying many of the general characteristics of cognitive skills. The book will be stimulating reading for psycholinguists, theoretical linguists, applied linguists and educators.