Language and nonlanguage factors in foreign language learning: evidence for the learning condition hypothesis

The study investigates why native and foreign languages are learned with a large performance gap and whether different mechanisms subserve them. Prior accounts emphasize either fundamental differences (FDH) or shared core functions (LCDH). This work proposes the learning condition hypothesis (LCH): language learning success is driven by similarity in learning conditions (naturalistic vs. classroom). Using data from 636 third-language (L3) learners in Hong Kong who learned Chinese (L1) naturalistically, English (L2) primarily in school, and French/German/Spanish (L3) in classrooms, the authors examined associations of learning success across L1–L3 while controlling for nonlanguage factors (e.g., musical background, SES, motivation). Converging analyses (general linear models, structural equation models, and machine learning) showed that the closer two languages were on the continuum of learning conditions, the stronger their association in learning success: significant associations were found between L1–L2 and L2–L3, but not between L1–L3. The results suggest learning conditions have important implications for L1–L3 learning success.