Size and composition of the lexicon in prematurely born very-low-birth-weight and full-term Finnish children at two years of age.

This paper focuses on the aspects of the lexicon in 66 prematurely born very-low-birth-weight and 87 full-term Finnish children at 2;0, studied using the Finnish version of the MacArthur Communicative Developmental Inventory. The groups did not differ in vocabulary size. Furthermore, the female advantage in vocabulary size was not seen in preterm children. The overall shapes of the trajectories for the main lexical categories as a function of vocabulary size were highly similar in both groups and followed those described in the literature. However, there were significant differences in the percentage of nouns and grammatical function words between the two groups. The results suggest that prematurity 'cuts off' the female advantage in vocabulary development. Furthermore, it also seems that there are differences between prematurely born and full-term children in the composition of the lexicon at 2;0. The findings support the universal sequence in the development of lexical categories.