Another good album hidden behind language barrier is Ilkim Oluanem's Girdap.I stomped upon this gem some months ago and since than i have listening it every now and then...
I mean lyrics are in Turkish ,but the music rocks (sorta progressive melodic black metal) and songwriting is just great.

I think I prefer hearing bands who aren't native speakers of English singing in their own language. Doesn't matter if I understand it or not (after all, we're talking about metal...) I just feel that singing in your native tongue gives a closer connection to what you're singing, and more than anything in music I like authenticity.

Yeah it's great when I can understand the words, but words are only part of the puzzle. I'd rather someone sang something meaningful that I can't understand (and I do speak other languages than English, so sometimes I get it) than sing stupid drivel in bad English. That really can ruin a song for me, honestly. Likewise hearing English-language singers who aren't american or canadian singing with an american accent. I find myself wishing they would just be themselves.