Introduction

When, in 1976, I was asked to write a chapter on language after age 5 for the first edition of this volume, I was struck by how many studies concentrated either on the period from 2 to 5 years or from 5 to 10. Far less frequent were studies which specifically bracketed the age span between, say, 3 and 7 years. A check through the major journals publishing developmental psycholinguistics shows that much the same holds true at the time of contributing to this second edition. Is there something crucial about the frontier age of 5 which makes many researchers either terminate or initiate their studies at this age? Does it simply reflect a focus before 5 on morphosyntactic and lexical problems, and after 5 on the complex sentential ones?

In this chapter I shall argue that 5 can be considered as a frontier age psycholinguistically. However, setting up experiments to concentrate on subjects under 5 years old, as if basic morphosyntactic and lexical acquisition were completed by 5 and the complex sentential only after 5, is questionable. It may stem from misconceptions based on surface behavioural mastery which neglect underlying representational changes. I shall therefore submit that fundamental changes take place in language development after age 5, not only with respect to complex intrasentential constructions, but also with respect to seemingly simpler categories at the morphologicolexical level, such as determiners.