Syllable position effects on English dark and light /l/ in comparison to /s/

Abstract

Effects of syllable position on the acoustic structure of speech sounds have been explored for different consonants, particularly for the lateral approximant /l/ in American English (AE). Sproat and Fujimura [J. Phonetics 21, 291–311 (1993)] reported that /l/’s spectral properties vary between initial (light) and final (dark) position, as in [l]ease vs. sea[ɫ]; this has been replicated in other studies. A similar effect was found for the fricative /s/ [Lombardo et al., J. Acoust. Soc. Am. 151, A45 (2022)], though the acoustic measures necessarily differed. We explored whether the magnitude of a light/dark difference varies by syllable position in AE words with both /s/ and /l/. Preliminary results show that the magnitude of positional differences for /l/ was uncorrelated with that of the /s/. Like previous studies, the positional effect for /l/ occurred with all vowels. Our measures are distinct acoustically (formants during the lateral resonance versus both peak frequency and the amplitude of mid-to-high frequencies during the fricative); therefore, the inconsistency may be due to measurement factors. Alternatively, the physiological mechanism may differ enough that speakers themselves differ; or, indeed, /l/ differences may be phonologized while the /s/ differences are not.