願望疑問文と失礼さ

In Japanese, using desiderative questions that include the desiderative forms -tai and -hoshii to ask superiors or elders about their desires can be considered impolite. Previous studies have explained that the impoliteness of desiderative questions is related to the pragmatic constraint in Japanese that speakers should avoid referring to the hearer’s private matters, including their own desires. Desiderative questions are typically impolite when used to ask the hearer about his/her requests to the speaker, and are not necessarily impolite when used to inquire about the hearer’s desire that does not carry the meaning of request. In Japanese, expressing desires does not necessarily indicate the intention of making a request. Therefore, when inquiring about the hearer's desires instead of asking them to make decisions about what or how to do in the given context, the speaker is taking a leading role in making the decision and the hearer is not expected to have the authority to decide. This is why desiderative questions in Japanese can be considered impolite when used to ask superiors or elders about their requests.