This paper aims to examine the use of the plain form by Thai Japanese speakers and Japanese native speakers as subordinates in business conversations with Japanese superiors. The study specifically focuses on the use of the plain form and its use in conjunction with laughter. This study also analyzes the contexts in which the plain form is employed and its functions within those contexts. The results show that Thai Japanese speakers primarily used the plain form in contexts to add information or examples, form questions and answers, and make references. Japanese native speakers employed plain form in context where they were referencing something, adding information or examples, or providing information. In the data from Thai Japanese speakers, multiple instances of the plain form occurring with laughter were observed, while a similar phenomenon was not found in utterances by Japanese native speakers. In addition, this paper identifies the fact that the plain form serves multiple functions, including clarifying information and expressing emotions, which were observed in both the data from Thai Japanese speakers and Japanese native speakers. Furthermore, the study uncovers some specific functions of the plain form, which were observed in the data of the Thai Japanese speakers only. These speakers are creating discourse markers when introducing new topics and adding a sense of enjoyment when the plain form occurs with laughter. The implications of this study could be applied to enhancing explanations of the plain form in Japanese education and business Japanese education.

This study analysed conversations between Japanese language learners and Japanese students as they interacted. This research focused on the following two points: ① What kind of experiences are discussed? ② What kind of empathetic response is expressed toward storytelling? The conversations were analysed using a conversational analysis method.. The following characteristics were revealed. Regarding ①, the students and language learners discussed common experiences as well as personal experiences. Additionally, they discussed their own experiences while also introducing the cultures of their home countries. When doing so, rather than simply to provide an informational context, they presented this information in a manner designed to pique the interest of the listener. By presenting this as a point of interest, a situation was created where the listener was more likely to be responsive. Moreover, when the speaker introduced culture through their personal experiences, the other party was able to participate in the discussion on an equal footing without being made to feel as though they lacked the prerequisite knowledge. It was found that this way of speaking created a structure of ‘learning from each other’ rather than ‘teaching the other person ⇔ learning from the other person’, which made it easier for both parties to talk about their experiences as they interacted. Regarding ②, it has been suggested that, through hearing about another person’s experiences and culture, one gains a better appreciation of that person’s culture while striving to better understand the individual themself. Some participants could also be seen reacting by seemingly empathising with the other person’s experiences.

Japanese learners may undergo a transformation in their awareness of "situations" (human relationships and contexts) through communication in various contact situations. In this study, cases were examined in which advanced Chinese learners experienced a "sense of failure" while speaking Japanese in contact situations involving requests . The study revealed the transformation of the learners' Taigu consciousness after they experienced failure in these contact situations and became introspective about communication as well as the perspectives of "others" not directly involved in the contact situations. Four advanced Japanese learners who are Chinese were interviewed and asked about instances where they had experienced a "sense of failure." The resulting data were analyzed. To elucidate the transformation of consciousness arising from each learner’s introspection, and that person’s perspective of "others," interviews were conducted using interpretation between the learner's native language (Chinese) and the target language (Japanese). Three key points became obvious from the results: (1) Learners can deepen their understanding of communication through introspection, but there are limitations, and negative emotions may arise. (2) Learners who have experienced a "sense of failure" in contact situations can deepen their understanding of communication by learning about the perspectives of others, freeing themselves from personal feelings of discouragement. (3) The method of incorporating interpretation between the learners' native language and Japanese, as presented in this study, is effective in eliciting and deepening learners' Taigu consciousness. In future Taigu communication education, as a learning method, it may be valuable for learners to engage with others to reevaluate their own experiences. Specifically, Japanese learners can bring experiences from their language life into classroom activities and resolve their concerns by learning about the perspectives of others. For this process, not only dialogue activities in Japanese but also methods involving written communication and translation into the learner’s native language may be effective.