Pretty sure they are more than capable of communication, especially since I'm having my head wrapped around part 3 at the moment. Even without outright speaking, the gorilla does communicate to Jotaro about the name of his stand and such and I'm pretty sure Polnareff put some faith into Iggy to somehow communicate to the other three about what has transpired.

So I do think it's possible. Would be interesting if the stand cry ended up being the way it communicated instead of it being a bit of a meme, but that's just a random thought I just had here.