I agree with Honorio. I think in most cases one needn't understand the lyrics to enjoy the music. Not knowing Icelandic never stopped me from liking Sigur Ros, for instance. It might be different with hip-hop artists and literary singer-songwriters, who rely heavily on their words, though.
While I agree that the bias is there, I think it would be hard to break. While I sometimes can appreciate music in languages I don't speak (I like some of Cesaria Evora's music for instance) for the most part I make more of an emotional "connection" when I can understand the lyrics.
Which means a bias against non-English lyrics for the most part.
My dislike of opera stems to some degree from that though I think I might dislike it even if sung in English because of the melodramatic performances.
This years been terrible for female performers. There's finally a lot of female solo singers but most of them blow. The brits are all Amy Whinehouse followers and than you have Katy Perry. "I Kissed a Girl" being sung by a women was clever when it was done in the 90s. Jill Sobule's lyrics were pretty witty so to have someone use the exact name and concept only watered down is pretty tacky. Our local top 40 Alternative rock stations are always missing women on their playlist but when they actually play women they play crap like Katey Perry, Evanessance and Paramoure. Women that try to sound like the trendy cockrockers dominating their playlist.