In the last decades, English has become increasingly important in Dutch society and, especially for adolescents, English functions as a second language (L2). This dissertation investigates how English (L2) in addition to Dutch as a first language (L1) affects the acquisition of the third languages (L3) French and German in Dutch secondary education. Six syntactic empirical studies are conducted in different groups of students enrolled in the first four years of either Dutch/English bilingual secondary education or mainstream Dutch education. Comprehension tasks and guided production tasks are used to examine the acceptance and use of Dutch XVSO word order and English Adv-V word order in French and German.
The context of a partially bilingual secondary school made it possible to investigate L1/L2 influence on L3 acquisition amongst students in different stages of secondary education, with varying amounts of L2 exposure and in two different language combinations (L1 Dutch–L2 English–L3 French and L1 Dutch–L2 English–L3 German).
This dissertation shows that secondary school students use both Dutch and English as transfer sources in L3 acquisition. A preference for either Dutch (L1) or English (L2) depends on the amount of English (vs Dutch) the students have been exposed to, the developmental stage of L3 learning the students are in and the L3 being learned. Making secondary school students and teachers aware that both the L1 and the L2 serve as background languages could help students learning a foreign language.