Seems to work best with songs in English grom the 70's-90's (Billy Joel, Gerry Rafferty...) Luttle luck with French songs, got weird matches that didn't sound

Seems to work best with songs in English grom the 70's-90's (Billy Joel, Gerry Rafferty...) Luttle luck with French songs, got weird matches that didn't sound at all like the original. Zero luck with tunes from clqssical music, even with very well known arias. May be an artifact of how this has been tested, and by whom...?