Acquisition of noun inflection in three languages: The role of input frequency and linguistic complexity.
Kołak, J., Granlund, S., Vihman, V., Engelmann, F., Ambridge, B., Pine, J., Theakston, A. & Lieven, E. (2018). Acquisition of noun inflection in three languages: The role of input frequency and linguistic complexity. Poster presented at the Budapest CEU Conference on Cognitive Development, Budapest, Hungary.
This study investigates the development of morphosyntactic competence in children acquiring morphologically complex languages, relating this development to input frequency and linguistic structure. Studies have shown that token frequency and phonological neighbourhood density (PND) impact on rates of learning (Ambridge et al. 2015). Various aspects of linguistic complexity like analysability, salience and regularity have also been shown to play a role, but it is not clear how these may differ across languages and how they interact with frequency. We elicited nominal case forms from 132 children (32–63 months) acquiring Estonian, Finnish or Polish. Participants were shown pictures of characters interacting with objects in 5 (Polish) or 6 (Estonian and Finnish) contexts requiring various case-marked forms. In each language we tested nouns varying in form frequency, with three nouns from each of 8-10 declension classes. The study was preregistered. We expected to find greater accuracy predicted by higher form frequency and larger PND in the input. Accuracy improved with age in all languages. As expected, we found interactions between frequency and PND for Estonian and Polish (Estonian: β=-0.17, SE=0.06, χ²(1)=7.03, p=0.008; Polish: β=-0.10, SE=0.05, χ²(1)=3.90, p=0.048), with a greater PND effect for lower than for higher frequency tokens; and a positive main effect of PND for Finnish (β=0.34, SE=0.23, χ²(1)=4.38, p=0.04). We also explored whether measures of linguistic complexity (distinctiveness, stem change complexity and syncretism) influenced accuracy and we found that the results were mediated by the typological features of each language. We discuss implications for usage-based theories of acquisition.