Acoustic consequences of articulatory variability during productions of ∕t∕ and ∕k∕ and its implications for speech error research

An increasing number of studies has linked certain types of articulatory or acoustic variability with speech errors, but no study has yet examined the relationship between such articulatory variability and acoustics. The present study aims to evaluate the acoustic properties of articulatorily errorful ∕k∕ and ∕t∕ stimuli to determine whether these errors are consistently reflected in the acoustics. The most frequent error observed in the articulatory data is the production of ∕k∕ and ∕t∕ with simultaneous tongue tip and tongue dorsum constrictions. Spectral analysis of these stimuli’s bursts shows that ∕k∕ and ∕t∕ are differently affected by such co-production errors: co-production of tongue tip and tongue dorsum during intended ∕k∕ results in typical ∕k∕ spectra (and hence in tokens robustly classified as ∕k∕), while co-productions during intended ∕t∕ result in spectra with roughly equal prominence at both the mid-frequency (∕k∕-like) and high-frequency (∕t∕-like) ranges (and hence in tokens ambiguous between ∕k∕ and ∕t∕). This outcome is not due to an articulatory timing difference, but to tongue dorsum constriction having an overall greater effect on the acoustic than a tongue tip constriction when the two are co-produced

Phonological Encoding in Mandarin Chinese: Evidence from Tongue Twisters

Models of connected speech production in Mandarin Chinese must specify how lexical tone, speech segments, and phrase-level prosody are integrated in speech production. This study used tongue twisters to test predictions of the two different models of word form encoding. Tongue twisters were constructed from 5 sets of characters that rotated pairs of initial segments or pairs of tones, or both, across format (ABAB, ABBA), and across position of the characters in four-character tongue twister strings. Fifty two native Mandarin Chinese speakers read aloud 120 tongue twisters, repeating each one six times in a row. They made a total of 3503 (2.34%) segment errors and 1372 (.92%) tone errors. Segment errors occurred on the onsets of the first and third characters in the ABBA but not ABAB segment-alternating tongue twisters, and on the onsets of the second and fourth characters of the tone-alternating tongue twisters. Tone errors were highest on the third and fourth characters in the tone-alternating tongue twisters. The pattern of tone errors is consistent with the claim that tone is associated to a metrical frame prior to segment encoding, while the format by position interaction found for the segment-alternating tongue twisters suggest articulatory gestures oscillate in segment production as proposed by gestural phonology.24 page(s