Young children's use of phrase structure and inflectional information in form-class assignments of novel nouns and verbs

The ability of 3.5- to 5-year-old children to use phrase structure and inflectional information in form-class assignments of novel nouns and verbs was investigated in two experiments. In Experiment 1 perfor mance was assessed on singular and plural nouns and on verbs with -s and -ing inflections. Accurate form-class assignments were made for all but the -ing inflection. This is attributed to a conflict between phrase structure and inflectional cues. In Experiment 2 a new sentence frame was used with verb -ing, which did not present conflicting cues. Performance was significantly better than in Experiment 1. The results are interpreted in terms of a model that proposes that phrase structure and inflectional cues to form-class are learnt independently but serve as interacting sources of information. The cues may interact in a complementary or competitive fashion. For English, the competition is resolved, in developmental terms, in favour of phrase structure cues as the more reliable source of information about form-class. This is adaptive for the grammar of English.