How referential are 'referential' children? Relationships between maternal-report and observational measures of vocabulary composition and usage.

This study examines the relationship between maternal-report measures of referential vocabulary and observational measures of referential vocabulary and usage in eight first-born middle-class children at 50 and 100 words. The results indicate that although maternal-report measures of vocabulary composition can be reasonably reliable, provided some attempt is made to restrict variation in the number of vocabulary items upon which they are based, such measures tend to exaggerate the relative importance of common nouns for the child in two ways; firstly, in the sense that they reflect differential maternal sensitivity to such word-types in comparison with other less-'referential' items; and, secondly, in the sense that they overestimate the extent to which such word-types actually occur in the child's spontaneous speech.