We have this really smart terrier, who, when she isn't being stubborn, perfectly understands commands like, "go into your cage" and "go outside." Sometimes we will give the commands without gesturing or looking in the desired direction, and the dog will go one way or the other, depending on whether we say "outside" or "cage." I don't think dogs understand grammar or anything like that, but they are smart enough to associate certain noises we make with certain behavior we expect of them. I would imagine that chimps can understand even more.
I do have a nightmare where corrupt politicians will have voting machines set up for chimps. It will feature a picture of a banana and when the chimp touches it, it will count as a vote! Anything is possible in a country where dead people vote for live politicians and, more recently, live people have voted for a dead politician. Our political system might go from bread and circuses to bananas and zoos!