Sequence and hierarchy in vocal rhythms and phonology

摘要: I explore the neural and evolutionary origins of phonological hierarchy, building on Peter MacNeilage's frame/content model, which suggests that human speech evolved from primate nonvocal jaw oscillations, for example, lip smack displays, combined with phonation. Considerable recent data, reviewed here, support this proposition. argue evolution motor control required two independent components. The first, identified by MacNeilage, is diversification phonetic "content" within a simple sequential "frame," would be reach nonhuman primates, simply intermittently activating phonation during displays. Such voicing requires laryngeal control, hypothesized to necessitate direct corticomotor connections nucleus ambiguus. second component, proposed involves imposing additional hierarchical rhythmic structure upon "flat" sequences typifying mammalian vocal tract oscillations flexible combinatorial capacity observed in modern phonology. hypothesize hierarchy resulted marriage preexisting seen other novel circuitry (potentially tool use and/or musical contexts). In turn, paved way phrasal syntactic hierarchy. these arguments using comparative data primates birdsong.