Vocal learning is one of the most critical components of spoken language. It has only evolved several independent times among mammals and birds. Although all vocal learning species are distantly related and have closer relatives that are non-vocal learners, humans and the vocal learning birds have evolved convergent forebrain pathways that control song and speech imitation and production. Erich Jarvis presents an overview of the various biological hypothesis of what makes vocal learning and spoken language special, how it evolved, and what differs about the molecular and neural mechanisms compared to other behavioral traits. (#38686)