口を酸っぱくして言う

The Japanese idiom '口を酸っぱくして言う' (kuchi o suppaku shite iu) literally translates to 'to speak until one's mouth becomes sour.' This vivid imagery refers to the sensation of one's mouth becoming dry or feeling a sour taste after talking for a long time, especially when repeating the same advice or warnings. The idiom conveys the effort and persistence involved in repeatedly advising or admonishing someone. It suggests that the speaker has invested considerable time and energy, to the point of physical discomfort, in trying to convey their message. This phrase emphasizes the speaker's dedication and the potentially difficult or frustrating nature of repeatedly giving advice, often to someone who is not listening or understanding. It implies a sense of exasperation or weariness on the part of the speaker, as they continue to reiterate their message despite the perceived lack of impact. The idiom highlights the emotional and physical toll of persistent communication in such situations. The 'sour mouth' metaphor is effective in conveying this feeling, as it is a common physical sensation associated with prolonged talking or stress. The idiom is commonly used in situations where a parent is repeatedly warning a child, a teacher is admonishing a student, or a mentor is guiding a protégé. It encapsulates the idea of providing persistent, often unsolicited, guidance with the hope of positive change, even when it feels like a tiring and thankless task. The phrase has been in use for a considerable time in the Japanese language, reflecting a long-standing cultural understanding of the challenges and importance of persistent advice-giving.