Individual differences in L2 achievement mirror individual differences in L1 skills and L2 aptitude: Crosslinguistic transfer of L1 to L2 skills

Studies with U.S. secondary second language (L2) learners have revealed individual differences (IDs) in first language (L1) skills and L2 aptitude and shown that these IDs are related to L2 achievement and proficiency. In this study, U.S. students were administered measures of L1 achievement, L1 cognitive processing, and L2 aptitude; followed through 2 to 3 years of Spanish courses; and administered standardized measures of Spanish achievement at the end of each year. Students were divided into high-, average-, and low-achieving groups according to their scores on the Spanish measures and compared on the L1 measures and L2 aptitude test. Findings showed significant overall group differences on most L1 measures and significant between-group differences on most L1 measures and the L2 aptitude test. IDs in L1 literacy, L1 working memory, and L2 aptitude best discriminated among students who completed 2 versus 3 years of Spanish. Results support claims that IDs in L2 achievement mirror IDs in L1 skills and provide evidence for the crosslinguistic transfer of L1 to L2 skills.