摘要：In the 1970s, Krashen proposed a monitor model, and by the mid-1980s, he had further revised and expanded his earlier theory to propose a model of input hypotheses. Krashen’s theory of second language acquisition has been well established for a long time and plays a significant role in the academic community. By utilizing CiteSpace, this paper analyzes the papers related to Krashen’s second language acquisition theory in the WOS database. Research on Krashen’s second language acquisition theory from 1974 through 2021 is summarized in the study, as is further discussion on the future development of Krashen’s theory. Krashen’s theory of second language acquisition has been mainly applied to the teaching of foreign languages. It is found that research on Krashen’s SLA theory can be broadly classified into four distinct phases of development and that the affective filter hypothesis is one of the most cutting-edge research topics in the field of Krashen’s SLA theory.
