Monkeys and primates can't speak. That much is certain. We know that some primates can learn to speak sign language and many can learn to understand human words, but they still can't talk to us. Until now, many people believed that was because they were physically incapable of speach, but a new study by the University of Vienna reveals that primates do have the physical ability to speak, with larynx, tongues and lips capable of it. Instead, they now believe that the problem lies in their minds -they simply aren't mentally capable of understanding how to use language and forming words.
So will they be able to learn to speak eventually? Maybe after another 1000 years or so of evolution.