In favor of the phonemic principle: a review of neurophysiological and neuroimaging explorations into the neural correlates of phonological competence

In the last thirty years, in vivo brain structural and functional exploration has sparked vivid light on the neural correlates of language. Along these lines, the study of phono- logical competence has offered a ‘neural view’ into the organization of basic speech- sensitive areas, improving the sensitivity of pre-surgical mapping and brain-computer interface-based communication. Nevertheless, only rarely the significance of these results has been recognized in the context of a century-long discussion around the theoretical, physical and cognitive consistency of the phoneme itself. Here we review recent investigations into speech perception, imagery and production at the segmen- tal level through neuroimaging and neurophysiological techniques, showing that phonemes are processed as discrete entities, which are categorized in cognition as unique products of their acoustic and articulatory features, despite the seamless flow of the speech signal. These results seem to expand the scope of the motor theory of speech perception