2018 Friday Poster 6589
Friday, November 2, 2018 | Poster Session I, Metcalf Small | 3pm
Children’s acquisition of person/number verb inflection in morphologically complex languages
J. Kolak, S. Granlund, F. Engelmann, M. Szreder, B. Ambridge, J. Pine, A. Theakston, E. Lieven
Introduction: Studies of naturalistic data have suggested that young children acquiring highly-inflected languages do so in a way that is largely error-free. However, overall low error rates in children’s production may hide higher error rates in certain parts of the paradigm (Rubino & Pine, 1998). To investigate this possibility, the current study examines children’s production of person/number marking in present tense verbs in two morphologically complex languages, Finnish and Polish, which differ in the complexity of the verb inflection pattern. Input-based accounts, which are mostly based on English morphological learning (e.g., Matthews & Theakston, 2006), predict that both the input frequency of a particular word form (token frequency) as well as the density of a word’s phonological neighbourhood (PND), predict rates of learning. Therefore, we investigate not only whether children make errors in inflection, but also where in the verb paradigm those errors occur.
Method: Seventy-seven native Finnish-speaking children (46 females; mean age: 49.4 months; range: 35-63) and 81 native Polish-speaking children (43 females; mean age: 48.7 months; range: 35-59) participated in the study, which employed an elicited production paradigm. The stimuli consisted of 32 verbs in each language. The verbs were chosen across a range of surface form frequencies and from 8 (Polish) and 11 (Finnish) verb classes varying in PND, with counts taken from CDS corpora and standard grammar dictionaries respectively. Each verb was presented as an action in a video on a laptop computer. Children were shown animations of different characters (1st, 2nd, 3rd person; singular and plural) performing the various actions, and they produced both the pronoun and the inflected present- tense form of the verb (e.g., “Minä uin” I swim-1sg; “Sinä imuroit” You hoover-2sg).
Results: Analysis with mixed-effects models revealed that, for both languages, despite overall low error rates (7-8%), children made more errors with verb forms with lower token frequencies in the input (Finnish: β=0.38, SE=0.06, χ²(1)=39.14, p<0.0001; Polish: β=0.26, SE=0.05, χ²(1)=29.47, p<0.0001) and
with verbs belonging to classes with lower PNDs (Finnish: β=0.17, SE=0.07, χ²(1)=5.78, p=0.016; Polish: β=0.21, SE=0.07, χ²(1)=8.36, p=0.004) (see Figures 1 and 2). In Finnish, but not in Polish, older children also produced fewer errors than did younger children (β=0.08, SE=0.03, χ²(1)=8.71, p=0.0032). The interaction between token frequency and PND was not significant in either language. The error analysis revealed a pattern whereby errors generally reflected the replacement of low frequency targets by higher-frequency forms of the same verb, or forms with the same person/number as the target, but with a suffix from an inappropriate conjugation class. It also indicated that person/number marking errors were higher in lower frequency contexts.
Conclusion: These findings suggest that successful models of children’s acquisition of verb morphology need to be sensitive to the statistical properties of children’s input, i.e., both token frequency (reflecting children’s retrieval of individually stored verb forms) and PND (children’s use of phonological analogy). The findings also demonstrate that types of errors made by children are influenced by the type of inflectional paradigm in the language.
References
Rubino, R. B. & Pine, J. M. (1998). Subject-verb agreement in Brazilian Portuguese: what low error rates hide. Journal of Child Language, 25, 35-59.
Matthews, D.E. & Theakston, A.L. (2006). Errors of Omission in English-Speaking Children’s Production of Plurals and the Past Tense: The Effects of Frequency, Phonology, and Competition. Cognitive Science 30(6):1027- 52.