Poo-poo's pop theories of brain lateralization. Suggests mostly adaptive. Inportant but seriously misreprented in pop discussion. Good discussion of Baldwinian evolution, genetic assimilation. Strong evolutionary arguments that there has been brain evolution to support language but not grammar.
Arguments revolve around required invariance of impact on brain.
There must have been sharp selection for brain size. Nothing anywhere in all of this about brain adaptations for tool use. Suggestion that early language would have been multimodal - spoken language requires specific adaptations. Extensive discussion of speech adaptations. Suggests early speech was embedded in gestures and exaggerated intonation with heavy use of ritualized markers.