The case-agreement hierarchy in acquisition: Evidence from children learning Basque

Children acquiring Basque begin producing absolutive agreement earlier in development than ergative inflection (Barreña, 1995; Ezeizabarrena, 1996). In this paper, I compare the acquisition of absolutive and ergative to dative agreement, which is also inflected on the auxiliary in Basque, in order to evaluate factors which may influence the order of emergence of inflectional morphemes, including input frequency, the position of the affix on the verb and feature complexity. Data from 20 bilingual and 11 monolingual children between 2;00 and 3;06 years old showed a consistent pattern; children acquired absolutive agreement first, then ergative, and dative inflection last of all. This sequence replicates the implicational hierarchy of cases found in many languages (Blake, 2001). I argue that the complexity of inflectional features of the agreement morphemes best predicts this developmental order, along with the assumption that children acquire the inflectional forms earliest which encode the fewest positive values for features.