Acoustic analysis of voiced “Stops” in Taiwanese: Intensity profiles and lenition patterns

Taiwanese exhibits an unusual set of voiced stops: /b/, /g/, and /l/, with /l/ included due to its “stop-like” characteristics and historical alternations with [d] in related languages. These segments are in complementary distribution with nasals /m, n, ŋ/. This study investigates the acoustic properties of these voiced “stops,” focusing on two questions: (1) How “stop-like” is /l/ in terms of intensity rise into the following vowel? (2) How is lenition manifested in medial position within this stop series? We analyzed a read speech corpus from 160 speakers (Liao et al., 2020, 2022). “Stop-likeness” was measured by the intensity rise (in dB) from the minimum during the consonant to the maximum during the following vowel. A mixed-effects regression model examined the effects of manner, place, position, and sociolinguistic factors. Results show that /l/ has a smaller intensity rise into the vowel than /b/ and /g/, yet it maintains a consistent contrast with /n/. In contrast, /g/ neutralizes with /ŋ/ word-medially, which may reflect Mandarin influence through cognates, where /g/ is dropped or corresponds to /w/ in Mandarin where /g/ is in Taiwanese. These findings highlight how lexical contrast and language contact shape variability in stop voicing in Taiwanese.