The roles of syllables and phonemes during phonological encoding in Chinese spoken word production: A topographic ERP study

Languages may differ in their proximate units of phonological encoding in spoken word production. The roles of syllables and phonemes when Mandarin Chinese speakers prepare spoken words remain controversial. In the present study, native Chinese speakers named disyllabic pictures that were preceded by briefly presented and masked prime words while electroencephalogram signals were recorded. Prime words were syllabically or phonemically related to the first syllable of targets or were unrelated. Variables of prime type (syllable overlap or phoneme overlap) and relatedness (related or unrelated) were manipulated in the experiment. Behavioral results demonstrated a critical interaction between prime type and relatedness, with a facilitation effect relative to unrelated primes appearing only in the syllable overlap condition. Spatio-temporal segmentation analysis indicated that syllable relatedness shortened the duration of Map 6 (around 285–410 ms), whose time window is associated with the phonological encoding stage. Comparatively, phoneme relatedness shortened the duration of Map 7 (around 410–480 ms) in a later time window. Onset latency analysis suggested an earlier onset for the syllable effect (284 ms) and a chronologically later onset for the phoneme effect (396 ms). Traditional waveform analysis revealed that the syllable overlap condition exerted significant effects on event-related potentials in the time window of 280–440 ms, whereas the phoneme overlap condition produced a weak effect in the time window of 400–440 ms in a few electrodes. Taken together, these findings substantiate the primacy of abstract syllables in producing Mandarin spoken words and provide initial topographic evidence that Mandarin speakers mentally represent subordinate phonemes at a later stage of word-form encoding. •We found an early syllable overlap effect and a later weak phoneme overlap effect.•Syllables constitute proximate units of phonological encoding for Chinese speakers.•The phoneme overlap effect was likely genuine yet subtle in Mandarin speaking.•Microstate segmentation offers new evidence for the proximate unit principle.