Proceedings of the Annual Meeting of the Cognitive Science Society

In learning morphology, do children generalize from their vocabularies on an item-by-item basis, or do they form globalrules on a developmental timetable? We use large-scale parent-report data to address this question by investigating relationsamong morphological development, vocabulary growth, and age. For three languages, we examine irregular verbs (e.g.go) and predict childrens correct inflection (went) and overregularization (goed/wented). Morphology knowledge relatesstrongly to vocabulary, more so than to age. Further, this relation is modulated by age: for two children with the samevocabulary size, the older is more likely to correctly inflect and overregularize, and the effect of vocabulary on morphologydecreases with age. Lastly, correct inflection and overregularization rates rise in tandem over age, and vocabulary effectson them are correlated across items. Our findings support that morphology learning is strongly coupled to lexical learningand that correct inflection and overregularization are related, verb-specific, processes.