Motor Theory of Language Origin

The motor theory is about the process by which language emerged and developed and how it functions now in human speech. The concern is with both synchronic and the diachronic aspects of language, language evolving over time and differentiating over space. In English alone we have half a million words and endless syntatic complexities, as Chomsky has demonstrated. Add the multitude of other languages that exist and have existed and it is apparent that language is a massive multiply-faceted fact-in time and space. Where did all the complexity come from? Whence the power of words seen in so many diverse forms of human interaction? How does this thread of sound tie our minds together?