ABSTRACT
Animal communication systems offer little room for individual variation. Most animal communication is about threats, territorial rights, and the pecking order, and in such matters, clear and unambiguous communication is paramount. Unlike animal systems, human language is very much bound to a single communication channel and one specific format. Human language not only allows for the formulation of infinitely many different messages but can also make use of entirely different channels. The sentences of human languages, sign languages included, are not monolithic blocks. Whereas in animal systems, even those of the great apes, the relationship between signal and meaning is as rigid as cast iron and entirely innate, there is no connection between the sound pattern of a word and its meaning. The animal system inside human includes many signals that are not produced orally, but involve other modes of expression—making a face, for instance, or sticking out your tongue the way children do to express disdain or malice.
