Key articles among the more than 100 that he has published include fundamental contributions to : a ) the understanding of infant babbling and how it lays foundations for speech, b ) various aspects of communication disorders and how they illuminate the language faculty and neurolinguistics, c ) a groundbreaking contribution to the understanding of how language evolved in humanity based on a theory of parental selection, and d ) the role of human life history ( with Barry Bogin ) in language evolution, based on the argument that the prolonged developmental period of humanity includes a childhood and an adolescence, phases that are absent in non-human primates, and both of which provide extensive and long-term opportunities for learning that lay groundwork for human language and culture.
