In studies on second language acquisition, there is a predominance of data concerning early language acquisition (Ortega & Iberri-Shea 2005) or language impairment (Graf Estes, et al. 2007). An absence of data dealing with later language development, as well as with cognitive factors influencing it has been identified (Tolchinsky, 2004; Nippold, 2007). Research has observed better performance in cognitive tasks of bilingual speakers (Bialystok 2006 for the case of executive control). Furthermore, the concrete role of working memory in predicting language development has been confirmed for the case of young bilingual speakers (Leseman, et al. 2009, Messer, et al. 2011). In order to close this research gap, a Language Development Panel (LiPS), a large-scale longitudinal study, focused on the age groups from 6 to 15 (6, 11 and 15 as starting cohorts) and included a large number of linguistic and non-linguistic variables. Data were collected using productive language tests and covers morphological, lexical, syntactical and discursive features, particularly addressing academic language skills (Cummins 2000, Gogolin & Lange 2010). The contribution will present results focusing on the role of working memory in predicting (academic) language development in later language development. Data will be analysed with hierarchical regression methods.