[Bill is, in fact, correct! The Beautifly does not in fact talk, and therefore it does not respond in any sort of verbal capacity.

It does, however, fly up like some kind of batshit avenging angel and start hovering menacingly between the girl and the man with his Psyduck, beating its stained-glass wings with a vaguely warning air.]

...Why — that really is something, isn't it? It's as though it did hear me.

[...]

Perhaps if you tried asking your duck to do something...?