<p>This study investigates whether monologue-like tweets are monologues. A questionnaire targeting undergraduate students was conducted three times (in December 2012 (n=240), February–April 2015 (n=92), and January 2016 (n=134) ). As a result, the frequency of monologue-like tweets was related to private speech tendency in the sample from 2012 and social speech tendency in the sample from 2016. Furthermore, with every year, the number of people who answered "taking notes" as a substitute for monologue-like tweets decreased, while that of persons answering "telling others" increased. These results suggest that the role of monologue-like tweets has changed from "private speech" to "social speech."</p>