Key Issues in Second Language Acquisition since the 1990s

The research field of the second language acquisition has been increasingly widened in recent years, and emerged various kinds of new theories. This thesis summarizes foreign and domestic researches’ key issues in this field since the 1990s according to theoretical framework of the second language research, then sorts out relative achievements from respective points of sociocutural theory; input, interaction and output in SLA; learner differences; external elements of learners, tacit knowledge and explicit knowledge and universal grammar and interlanguage representations, and looks into the future development, so as to make domestic learners better understand the current researches of this field and increase the general level of our foreign language education and teaching