be understood as the result of a complex adaptive system. Complex adaptive systems are characterized by interacting sets of agents (which can be individuals, neurons, etc.), where each agent behaves in an individually adaptive way to local conditions, often following very simple rules. The sum total of these interactions nevertheless leads to various kinds of emergent, systemwide orders. Biological evolution is a prime example of a complex adaptive system: Individuals within a species (a system) act as best they can in their environment to survive, leading through differential reproduction ultimately to genetic changes that increase the overall fitness of the species. In fact, evolution can be understood as the name we give to the emergent results of complex adaptive systems over time. One can also view the brain itself as a complex adaptive system. This is because brain circuits are not independent of each other. Processing in one area affects processing in connected areas; therefore, processing changes in one areawhether due to biological evolution or learninginfluence (and select for over evolutionary time) changes in other areas.A number of neural systems relevant specifically to language interact with and influence each other in important ways. Syntax depends fundamentally on the structure of semantics, because the function of syntax is to code higher level semantic information (e.g., who did what to whom). Semantics in turn depends on the structure of conceptual understanding, whichas will be reviewed lateris a function of brain structure. These structures are in turn the result of biological adaptation: Circuits that result in conceptual understanding that is relevant and useful to a given individuals (ever-changing) environmental realities will be selected for and will spread over evolutionary time.(...)Therefore, language evolution itself will be strongly constrained by pre-existing cognitive abilities within each generation. Changes affecting the perception of linguistically relevant signals would have been favored only to the extent that they increase the individuals ability to perceive and rapidly process the acoustic signals already used by others for language. Changes affecting the production of linguistically relevant signals would be favored only to the extent that they could be understood by the preexisting perceptual abilities of others. Signals too complicated or subtle for others to process would not be adopted and, hence, mutations influencing them would not likely spread.(...)Classical Language AreasBrocas and Wernickes areas were the first cortical regions to be associated with specific linguistic abilities. Brocas aphasics display nonfluent, effortful, and agrammatical speech, whereas Wernickes aphasics display grammatical but meaningless speech in which the wrong words (or parts of words) are used (Bear, Connors, & Paradiso, 2007; Damasio et al., 1993). Brocas area is located in the posterior-inferior frontal convexity of the neocortex, whereas Wernickes area is localized to the general area where parietal, occipital, and temporal lobes meet. For most people, these areas are functional for language primarily in the left hemisphere.Additional areas, adjacent to, but outside these classic language areas, appear to be important for these aspects of language processing as well. Brocas and Wernickes aphasias (i.e., the specific types of language deficits themselves) are not exclusively associated with damage to Brocas