The Least a Second Language Acquisition Theory Needs to Explain

Theories of second language acquisition (SLA) are attempts to explain well‐attested empirical findings about relationships between process and product in interlanguage development and universals, and variance in learners and learning environments. An important component of such theories will be one or more mechanisms to account for interlanguage change. While theories differ in scope and so often relate only to partial descriptions, they must account for major accepted findings within their domains if they are to be credible. Identification of “accepted findings,” therefore, is an important part of theory construction and evaluation. Such findings will be the least an SLA theory needs to explain. Sample accepted findings on learners, environments, and interlanguages are proposed along with some implications for current SLA theories.