I think the player will read all file/song names that the player is able to read (all the languages you are able to pick from the H10's settings).
However, considering that the H3xx (and I think the H10) text viewer is able to show Korean, Japanese, Chinese, and English, I think it would be safe to assume that the H10 will be able to display foreign characters in a text file.
Apparently you're a big BoA fan! I'm one too!! (Although not as active as you
)
안녕하세요~~