This post covers more than this thread's topic so please read on only if you're interested...
I've never really minded the non-English vocals. Somewhat similar to Ken's experience, 90% of my enjoyment is related to the musical complexity/depth (including the vocal lines/harmonies) of the compositions and performance. There are perhaps a few more great lyricists in existence than Ken mentioned but, in totality, they number in the less than 0.5 percentile of the folks that are out there.
Part of my musical evolution is that, as a child, my folks started me on classical music (inlcuding numerous non-English choral works) very early on and I really did not become aware of more modern music until I was about 7 when I heard the full version of the Moody Blues' "Night's In White Satin" for the first time.
That experience was catalyst for me to shift time away from my classical records to the FM radio stations of the time where I quickly began developing a taste for The Beatles, Elton John, Queen, Pink Floyd and Genesis. Purple, Tull, Yes, Crimson, Heep, Zeppelin and Wishbone Ash came later. By 1975, I was in full-fledged hard/prog rock mode and starting to look beyond the English-speaking world for new sounds.