Being polite while fulfilling different discourse functions in online classroom discussions. - Diane L. Schallert; Yueh-hui Vanessa Chiang; Yangjoo Park; Michelle E. Jordan; Haekyung Lee; An-Chih Janne Cheng; Hsiang-Ning Rebecca Chu; SoonAh Lee; Taehee Kim; Kwangok Song (Comput. Educ., 2009)