Among the vast multitude of animal species, languagelike communication is the anomaly, not the rule. It is not just unusual or rare; it is essentially nonexistent except in one peculiar species: Homo sapiens, and I am not confining my definition of language to verbal communication or communication systems with exactly the grammatical structure that can be found in all human languages. I mean language in a generic sense: a mode of communication based upon symbolic reference and involving combinatorial rules that comprise a system for representing synthetic logical relationships among symbols. Under this definition, sign languages, mathematics, musical scores, and many rule-governed games might qualify as languagelike, but not bird songs, vervet monkey alarm calls, honeybee dances, or humpback whale songs (some animal communicative behaviors often cited as languagelike ), because these nonhuman activities lack both symbolic and combinatorial function, although they resemble language in certain superficial features. No more than a minute vocabulary of meaningful units and two or three
combinatorial rules are necessary to fulfill these criteria. A childlike five-or 1 0-word vocabulary and a grammar as simple as toddlers' twoword combinations would suffice. And yet, even under these loosened criteria, no other species on earth has evolved any form of communication that even remotely qualifies. This is an important, and little appreciated paradox, because it indicates that the complexity of language (e.g., the numbers ofwords and interdependent rules of grammar) is not the issue. Why are there no simple languages in the rest of the animal kingdom?