This emphasis on sounds was among the list of motorists for Kūkai's championing of the phonetic creating system, the kana, which was adopted in Japan across the time of Kūkai. He is usually credited Together with the creation of the kana, but there is apparently some doubt about this story https://baglamukhi-shabar-mantra54320.dbblog.net/108259/the-smart-trick-of-mantra-that-no-one-is-discussing