Case marking in child L1 and early child L2 German

We examine case marking in spontaneous production data from four successive bilingual children and in experimental data from 21 successive bilingual and 14 monolingual children. A clear difference surfaces between spontaneous production data and experimental data. Based on the spontaneous production data, we conclude that the four successive bilingual children behave like the monolingual children studied by Eisenbeiss, Bartke & Clahsen (2006). They rarely produce structural case errors and often produce lexical case errors. But under experimental conditions, successive bilingual and monolingual children produce a large number of structural case errors, in particular with structural dative. Our experimental findings from the monolingual children are in stark contrast to those in Eisenbeiss et al., which are based on spontaneous production data only.