Kanzi is a semi-famous chimp who has, according to his owners, the ability to understand and communicate language. The experiments that show proof of this are, in my opinion, similar to most other spurious experiments that have "proven" that other apes have language. In Kanzi's case:

"In addition to single words, Kanzi has demonstrated unequivocal understanding of thousands of novel spoken sentences with syntactically complex structures including embedded phrases, pronouns, case markers, and absent referents. His comprehension of spoken language is at least equivalent to that of a 2-1/2 year old child. "

The knuckle draggers basically point and bark on command, can recognize many many words, and then get their picture taken wearing sweaters or opening Christmas presents. The scientists presenting these findings don't tell you that this communication isn't considered by most language experts to be language. And they wouldn't dare to show Kanzi eating turds, or going spastic, or eating bugs, or doing these other things that surely he wants to and needs to do, as a wild creature. No, the stuff submitted to the public is nice and neat. All these tricks and charades cause us to forget to ask the question: "what is language, and do these animals truly exhibit it?" Human language, is of course, not mere communication. All animals communicate on some level, and everyone knows that. Anyone who has had a dog knows that a dog can tell you when it wants to go for a walk, is hungry, and by it's barking, when it's pissed. Essential to language, and missing completely from all other animals, from dolphins to the smartest of cardigan donning chimps, is creativity. We're talking a difference in kind, not degree. Dorothy Chaney, professor of biology at the university of Pennsylvania says,

"We know that at least some species of non human primates possess in their natural communicative repertoire a small number of calls that serve as semantic labels for objects. Nonetheless, these same animals never seem to create new calls or new labels for objects."

Even a child younger than to can give a name to something. It instinctively learns words and language without being taught. These animals do not and can not make these leaps. I think, however, we can sometimes miss what is probably the real sad thing, the real issue. These same "language able" monkeys and apes that Scientists dress up like babies in diapers and compel them to participate in human pastimes, would probably rather be in their natural habitat, swinging from trees, and eating their own poop.

Kanzi

Why Animals Don't Have Language