Donuel
Pressing buttons isn't the dog talking, it is the button talking. The dog is associating the colour with an outcome or response. And it has to be learned. I have seen cats do it, though it usually results in a button saying "food" more often than not.

I have heard many stories about sheepdogs responding to situations without command. And my GF's Jack Russel used to sleep on her aged father's bed and one night she started barking, right out of character, so we went to see him fallen out of bed. No training, just loyalty and thinking, and communicating.