Linguistic differences and language design.
A small number of discrete choices ('parameters') embedded within a system of otherwise universal principles create the extensive superficial differences between unrelated languages like English, Japanese, and Mohawk. Most current thinking about the evolution of language ignores or denies the existence of these parameters because it can see no rationale for them. That the human language faculty is organized in this way makes more sense if language is compared to a cipher or code. As such, it would have a purpose of concealing information from some at the same time as it communicates information to others.
Baker
Mark C.
MC
Department of Linguistics, Rutgers University, 18 Seminary Place, 08901, New Brunswick, NJ, USA