A human language is a system of remarkable complexity. To come to know a human language would be an extraordinary intellectual achievement for a creature not specifically designed to accomplish this task. A normal child acquires this knowledge on relatively slight exposure and without specific training. He can then quite effortlessly make use of an intricate structure of specific rules and guiding principles to convey his thoughts and feelings to others, arousing in them novel ideas and subtle perceptions and judgments (Chomsky, 1975) It would surprising indeed if we were to find that the principles governing [linguistic] phenomena are operative in other cognitive systems, although there might be certain loose analogies, perhaps in terms of figure and ground, or properties of memory, as we see when the relevant principles are made explicit. Such examples illustrate that there is good reason to suppose that the functioning of the language faculty is guided by special principles specific to this domain. (Chomsky, 1980). from http://pinker.wjh.harvard.edu/articles/papers/Pinker_Jackendoff.pdf