  Before leaving the question of language evolution, it is necessary to mention a recent paper by Hauser, Chomsky and Fitch 2002 on this  topic. First, they distinguish (2002:1571) what they call the  ‘faculty of language in the narrow sense,’ or  ‘FLN,’ from the ‘faculty of language in the broad  sense,’ or ‘FLB.’ The FLN is the “abstract  linguistic computational system alone…which generates internal representations and maps them into the sensory-motor interface by the phonological system, and into the conceptual-intentional interface by the (formal) semantic system.” (Ibid.) The FLB  includes the FLN plus all the other systems (motor systems,  conceptual systems, perceptual systems, and learning skills) which  contribute to language acquisition and use.