Charkova, K. D., & Halliday, L. J. (2011). Second- and foreign-language variation in tense backshifting in indirect reported speech. Studies in Second Language Acquisition, 33, 1-32.
摘要：This study examined how English learners in second-language (SL) and foreign-language (FL) contexts employ tense back shifting in indirect reported speech. Participants included 35 international students in the United States, 37 Bulgarian speakers of English, 38 Bosnian speakers of English, and 41 native English speakers. The instrument involved speech scenarios in two time settings-immediate and delayed report-and questions about the participants' reasons for back shifting tenses or not. The results revealed that FL environments foster the acquisition of back shifting as an automatically applicable grammatical rule, whereas SL contexts facilitate awareness of pragmatic and semantic aspects of tense back shifting. Adapted from the source document
关键词：applied linguistics, English as a second/foreign language learning, Reported Speech, English Language Learners, English as a Second Language Learning, Tense, Learning Environment