I thought it was said earlier in the thread that 'buh' was a sound effect for farting. So its either a rude-like speach pattern or actual fart … either way is hilarious.
@Aohige:
Eh, it seems a lot of people are convinced the head and the lower body is different samurai because "they don't have the same speech pattern, the lower body says "buh" at the end".
Let me clarify one thing, that is a possibility, but also keep in mind, "bu" is sound of fart.
It's plausable that it's just a childish joke by Oda that the lower half is literally speaking out of its ass.
It's just a possibility…. but pretty nasty.