Isolating second language learning factors in a computational study of bilingual construction acquisition

The study of second language acquisition (SLA) is often hindered by substantial variability in the background of learners, their learning process and the input they receive. This diversity often makes it difficult to isolate specific learning factors and study their impact on L2 development. We present a computational study of SLA as an alternative methodological approach. By applying a usage-based computational model of construction learning on bilingual (German and English) input data, we analyze various learning variables in isolation. In particular, we investigate three factors: ratio between the amount of L1 and L2 input, age of L2 onset, and L2 frequency distribution. Our results are in line with experimental findings on the facilitatory effect of lower L1/L2 ratio and balanced L2 frequency distribution. We found no negative effect of later age of L2 onset on proficiency, which might be due to positive cross-linguistic transfer between German and English constructions.