Poster B64, Tuesday, August 20, 2019, 3:15 – 5:00 pm, Restaurant Hall
Neural correlates of lexical tone and intonation in tonal and non-tonal language speakers
Pei-Ju Chien1, Angela D. Friederici1, Gesa Hartwigsen1, Daniela Sammler1;1Max Planck Institute for Human Cognitive and Brain Sciences
It has been shown that pitch processing can be tuned differently according to the linguistic function carried by pitch information. However, it is unclear how different types of linguistic pitch are organized in neural networks for speech and language and how speakers' language backgrounds influence these representations. Here, we investigated the neural correlates underlying the perception of lexical tone and intonation in tonal and non-tonal language speakers. To this end, we adopted Mandarin Chinese (hereafter Mandarin) as materials and compared Mandarin and German speakers’ processing. We conducted an fMRI experiment and tested the categorization of tone and intonation, and a control baseline (voice gender categorization). Monosyllabic stimuli ‘bi’ spoken with two lexical tones (tone 2, ‘nose’, tone 4, ‘arm’) and two intonation types (statement, question) by four Mandarin speakers (2 males) were audio-morphed by steps of 12.5% to create pitch-varied continua of tone, intonation and gender, respectively. During scanning, participants categorized the audio-morphed stimuli for either tone, intonation or gender in separate blocks. Comparisons of task-related activity indicated that between-task differences were found only in Mandarin speakers. Between-group differences were found only in the tone task. First, neural activity of tone and intonation in Mandarin speakers segregated in the bilateral parietal cortices for tone against intonation and in the right frontal cortex for the reverse contrast (intonation vs. tone). The parietal activity for tone vs. intonation included bilateral angular gyrus and superior parietal lobule, likely reflecting semantic processing. Frontal areas for intonation vs. tone included right middle frontal gyrus (MFG), inferior frontal gyrus (IFG), pre-supplementary motor area (preSMA) and insula, possibly reflecting stronger recruitment of pitch contour evaluation in intonation and a difference in cognitive control between tasks. Both tasks overlapped (against gender) in the left supramarginal gyrus (SMG), possibly indicating common involvement of phonological processes. In German speakers, task-related activity of tone and intonation (against gender) largely overlapped in the left MFG, IFG, premotor cortex (PMC), preSMA, SMG, insula and cerebellum, suggesting that tone and intonation might not be discriminated by their linguistic functions but similarly related to phonological and pitch contour processing and share comparable demands for cognitive control. When comparing between groups, Mandarin speakers showed significantly stronger activity in the tone task in the bilateral insula, posterior cingulate gyrus, putamen and cerebellum, suggestive of stronger involvement of semantic processing and tonal articulation in native speakers. Both groups overlapped in the intonation task in the left IFG, insula, PMC and bilateral preSMA, possibly indicating similar processes across native and non-native speakers. Together, these findings demonstrate the interplay between linguistic pitch processing and speakers’ language backgrounds.
Themes: Prosody, Speech Perception
Method: Functional Imaging