Despite contrary research findings, many laypeople still claim that starting second language (L2) instruction early yields linguistic advantages. This assertion is again undermined by a 5-year longitudinal study conducted in Switzerland testing the English language skills of 636 secondary-school students who had all learned Standard German and…

In this article, I describe studies conducted over 25 years with secondary and post-secondary L2 learners in the United States. The evidence from these studies shows that there are important connections between students' early L1 skills and their L2 aptitude and L2 proficiency and that individual differences in students' L1 skills in elementary…