Light verbs and the flexible use of words as noun and verb in early language learning

The present thesis investigated two questions: (1) is there a correspondence between lexico-semantic categories like object and syntactic categories like noun in acquisition, and (2) can the late emergence of action nouns be explained by their use in longer, "complex predicate" constructions (CP), such as Have a hug?;Paper 1 examined the use of words that can appear as noun or verb, in the speech of nine English-speaking children (aged 1;3--2;6) and their caregivers. Children showed a strong polarization in their productions, using a majority of object words consistently as nouns and non-object words consistently as verbs. However, children also showed some flexibility, and used fewer non-object words as nouns than object words as verbs.;Paper 2 investigated words used by caregivers in CPs to those that were not in the speech of nine English-speaking children (aged 1;3 to 4;6). On average, words used in CPs by caregivers emerged later in child speech that non-CP words. Also, at early stages children had not mastered the use of verbs required for CPs. It was concluded that words used in CPs (i.e. action nouns), may emerge late due to their use in these expressions, and not due to a problem understanding the semantics of action words.