There are sound effects! Or you mean specifically for the sex scenes? ( I read your comment below )
It would be cool but I think it could end up poorly. And I would want all the moans to sound like theyre from the same person so I'd prolly need voice actors and it'd take a ton of extra time.
I plan to translate the game when it's further along! Maybe I'll translate chapters 1-4 before the game is done though..