The validity of word age-of-acquisition ratings : a longitudinal study of a child's word knowledge

The age at which a child first said and read each of 94 picturable nouns was recorded. At ages 9:6 and 11:6, the child was asked to estimate the age she first said these words. Her age-of-acquisition estimates were found to be highly correlated with the actual ages of first saying and reading the words. Age-of-acquisition estimates were also highly stable over the two-year-period. Frequency of saying the words and ease of saying them appeared to be important factors used in making age-of-acquisition judgements. The results support the validity of age-of-acquisition ratings used in memory research.