Tonal languages provide a window for tracing the hierarchical transformation of the pitch of a sound from early sensory to later cognitive stages of processing in the human brain. Hemispheric laterality of pitch is driven by multiple dichotomies or scalar features that apply during real-time intervals at cortical and subcortical levels. Using functional neuroimaging, we show that pitch processing recruits the hemispheres differentially as a function of its phonological relevance to the listener. Mismatch negativity, a neural index of early, cortical processing, shows that pitch processing is shaped by the relative saliency of tonal features. Frequency following response, a neural index of brainstem pitch encoding, shows that enhancement of pitch features is sensitive to rapidly-changing segments of tonal contours, and that ear asymmetries can be modulated by functional changes in pitch based on linguistic status. We conclude that nascent representations of acoustic-phonetic features emerge early along the auditory pathway.

Index Terms: perception; pitch; lexical tone; intonation; cerebral cortex; brainstem; auditory electrophysiology; functional brain imaging; experience-dependent plasticity; hemispheric specialization; cue-specific; domain-specific; Mandarin; Cantonese; Thai