Phil is a mute chimpanzee who has dark brown fur. Although he is mute, he is an avid (having or showing a keen interest in or enthusiasm for something) reader where he can communicate with American Sign Language and can read properly with Mason being able to translate his sign language. In near stark contrast to Mason, Phil is the "Oscar" of the Chimpanzees as Philip is more dirty and temperamental.
Phil is the lighter colored of the two chimps and he is a mute who uses sign language as his means of communication and he even signs while he is dreaming. He knows how to read the English language and often interprets things for Mason. Although ASL is traditionally used by the deaf- and the hearing-impaired, Phil is neither, as evidenced by "Assault and Batteries" when he jammed bananas in his ears to drown out King Julien's obnoxious music.
Interestingly, in the Penguins of Madagascar comic book, he is able to talk. However, PoM TV and any other works in that range are not canon.