Second language acquisition research and practice have long recognized the value of classroom interactions— among learners, between learners and teachers, and btbbibobopabpclomollfdidrdbnrfsition, particularly when these interactions involve negotiation of meaning. (See Moss & Ross-Feldman, 2003, for a prolcefpobpboerelirpflptbobobbba in the major shift toward communicative approaches in language teaching that began in earnest in the late 1970s orlepllobobbiplbobpboebop and practitioners have turned to problem-based learning