Wilkins & Wakefield suggest that changes in the hominid brain made it uniquely “preadaptive” for language, yet no precursor functions served as adaptive substrates to the emergence of language. We present contrary evidence that the ability to discriminate and process rapid and complex auditory information is a cross-species function subserving communication processes including, but not limited to, human speech perception. We suggest that auditory temporal processing served as an evolutionary precursor to speech processing and consequent language development in humans.

Thomas & Karmiloff-Smith (T&K-S) raise an issue of considerable theoretical importance: Are developmental disorders like cases of adult brain damage? However, a related question: Are developmental disabilities the same in children and adults? is rarely addressed. Failure to consider the cumulative and differing effects of aberrant development across the life span confounds the current literature on both developmental dyslexia and Specific Language Impairment.