1 Transfer effects in the acquisition of English as an additional language by bilingual children in Germany Peter Siemund and Simone Lechner, Hamburg Abstract In this paper, we investigate the language development of children with migration backgrounds who live in Hamburg and are currently learning English as a foreign language in school. With data collected from bilingual Russian‐German, Turkish‐German, and Vietnamese‐German children, we evaluate both the quality and the quantity of transfer effects. The linguistic features investigated are subject‐verb‐agreement and the use of articles. We interviewed 160 12‐ and 16‐year old test subjects, distributed equally according to language cluster and age, comparing the results to test subjects’ developmental levels in their heritage language and German, which were investigated independently. In addition to the main cohorts, additional cohorts of L1 speakers of Turkish, Russian, and Vietnamese with English as an L2 as well as adult bilinguals in Germany were interviewed. After factoring out language external phenomena, we can observe that both L1 and L2 have an influence on the acquisition of English, but that these effects depend on the phenomenon investigated and the language pairs involved. Our findings suggest a model of language transfer in which the grammatical status of a phenomenon interacts with the learner’s developmental level yielding qualitatively different transfer effects. 1. Introduction The number of children of multicultural descent in Germany is growing, especially in urban areas. According to the board of statistics for Hamburg and Schleswig‐Holstein, 46% of the population under the age of 18 in Hamburg had a migration background by 2011 (Statistisches Amt für Hamburg und Schleswig‐Holstein 2011). In the German context, children are considered to have a migration background if one of their parents does not have German citizenship or was born abroad. Following a more general trend, urban areas embody the pivotal attractors of global migration, as they offer labor, a good infrastructure, and potential for economic and social advancement. In Hamburg alone, an estimated number of 150 – 200 languages can be encountered, with nearly every nation being represented. Major countries of origin include Turkey, Russia, Poland, and Ukraine, though Hamburg also harbors substantial migrant populations from China, Vietnam, West African countries, and India. This means that children with highly diverse linguistic profiles and language biographies enter the education system. This diversity is typically seen as a problem, as deficits in the language of their environment (i.e. German) as well as their home Siemund, Peter and Simone Lechner (2015) ‘Transfer effects in the acquisition of English as an additional language by bilingual children in Germany’, in: Hagen Peukert (ed.) Transfer Effects in Multilingual Language Development. Amsterdam: Benjamins.