Many people speak more than two languages. How do languages acquired earlier affect the learnability of additional languages? We show that linguistic distances between speakers' first (L1) and second (L2) languages and their third (L3) language play a role. Larger distances from the L1 to the L3 and from the L2 to the L3 correlate with lower…

In bilinguals and second language learners, the native (L1) and nonnative (L2) languages coexist and interact. The L1 influences L2 production via forward transfer, as is seen with foreign accents. However, language transfer is bidirectional: even brief experience with an L2 can affect L1 production, via backward transfer. Here, we review the…

The present meta-analysis examined the overall average correlation (weighted for sample size and corrected for measurement error) between passage-level second language (L2) reading comprehension and 10 key reading component variables investigated in the research domain. Four high-evidence correlates (with 18 or more accumulated effect sizes: L2…

Researching the longitudinal development of second language (L2) learners is essential to understanding influences on their success. This 7-year study of oral skills in adult immigrant learners of English as a second language evaluated comprehensibility, fluency, and accentedness in first-language (L1) Mandarin and Slavic language speakers. The…

Given that this special issue is devoted to the acquisition and processing of inflectional morphology by second language (L2) learners, the question in the title may appear redundant. However, recent research on first language (L1) and L2 morphological processing has challenged basic assumptions about the status of inflectional morphology in…