I listen to Japanese songs, so I often need the lyric. I'm using the musicbee player, but I can't use it to display Japanese lyric. I need another music player for Windows that supports adding your own lyric (e.g. in text file).
Quod Libet is a cross-platform and free/libre music player (which I also recommend for huge music collections, as iTunes alternative, and for managing/displaying custom tags) that allows to save the lyrics of a song.
To enter/edit the lyrics of a song, you can press Ctrl+i (or right-click and select "Information") and select the lyrics tab, which is a simple textarea:
The lyrics get saved as text files (a folder for each artist, with a text file for each song, named after the song’s title).
You can even search for songs with certain lyrics:
~lyrics = なぜ