From the FAQ: What are the backward lyrics in Ya Hozna?

This is a joke on the self-appointed guardians of
public morals who got themselves whipped into a frenzy of
righteousness about "Satanic backward masking," a process
in which secret messages are allegedly inserted into rock
songs, revealed by playing the record backwards. In "Ya Hozna"
the members of Zappa's band are heard to be singing
unintelligible gibberish, and the lyrics sheet says "backward
vocal, you figure it out." Well, I had the LP and a belt-drive
turntable, so I was able to figure it out. It's just as
nonesensical played backwards (and pretty much sounds the
same as well) I guess they played around until they found
some nonesense syllables that sounded the same forward as
backward (as "ya hozna