Local Files with Foreign Characters (Non-English) Not Showing in Library

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I have lots of Japanese music with Japanese characters and German music. When I search in hiragana, katakana, kanji, and in German (umlauts), for example, I cannot find the associated songs in my library even though I can go through the library on my computer to locate them. I have been changing umlauts (i.e. ü to u) and katakana (i.e. フリー・アズ・ザ・ウインド　to Free as the Wind) to remedy this so far. In turn, I can find the newly, though somewhat incorrectly, named songs now through the Spotify desktop app. However, why not enable the search function to find non-English characters?