In an interview with Jeff Goldsmith, Silver said, "We’re working on the sequel right now, to the prequel, and so the excitement is – I’m not gonna tell you, but – are they gonna talk or not? Part of the challenge was how to get across what was happening between the apes without words. In the end I think it was a good challenge for us. It created better storytelling."
The quote leaves the door wide open for speculation in regards to where the follow-up will go with talking apes. There is certainly no need to rush things, I think. We don't need to see speaking apes from minute one, but it would be nice to see them evolve further through the film.