That vid was from before I joined (we're bigger now).  Usually we learn it phonetically, which is easier with the regular languages.  We're not *memorizing* the music (except the soloists for Katamari Damaci last summer, but they know Japanese anyway).  I sang in church choir and school chorus growing up, so I'm familiar with singing in Latin, German, Spanish, some French.  I also took Spanish in high school, German in high school and college, and I have a smattering of Latin also, so it's easier for me to pick up the foreign-language songs than some of the other singers.  We're rehearsing one now that switches between German and Latin.