The role of duration in the perception of vowel merger

Abstract

Speakers with vowel categories that are considered merged by traditional measures (e.g., F1 and F2 measurements at a single time point) may contrast vowel classes in dimensions beyond vowel quality, such as duration. Durational differences among vowel classes have been observed to persist even in cases of spectral overlap (e.g., Fridland et al., 2014;Labov & Baranowski, 2006), suggesting that duration may serve as a contrastive cue among spectrally-merged or near-merged vowel classes. This paper examines the role of duration in perception in two communities: Youngstown, OH, which exhibits multiple patterns of merger and distinction among pool-, pull-, and pole-class words, and Burlington, VT, whose residents are largely unmerged. This paper presents the results of a forced-choice identification task consisting of lexical stimuli with synthetically manipulated vowel-liquid durations, analyzed in light of participants' production data. Results indicate that duration influences vowel categorization and is utilized more extensively when spectral cues are diminished or unavailable.

Perceptual vowel contrast reduction in Australian English /l/-final rimes

“…In contrast, listeners could not identify /l/, when /l/ and the preceding vowel were replaced by white noise: Listeners could identify belly from [be##], but not from [b##i] (West, 1999). Vowel identification has been examined in /l/-triggered vowel mergers in several dialects of English (Thomas & Hay, 2005;Loakes, Clothier, Hajek, & Fletcher, 2014b;Wade, 2017). Listeners from Melbourne, Australia showed a limited ability to distinguish /el/ from /ael/ in a word identification task with minimal pairs (e.g., Alan-Ellen) (Loakes, Hajek, & Fletcher, 2010a, 2010b, 2010c, 2011Loakes, Graetzer, Hajek, & Fletcher, 2012;Loakes, Clothier, Hajek, & Fletcher, 2014a;Loakes et al, 2014b).…”

“…Some speakers of New Zealand English were able to distinguish minimal pairs differing in /el/ and /ael/ despite merging /el-ael/ in production (Thomas & Hay, 2005). In Ohio English, listeners could distinguish spectrally merged /oʊl-ul/ (e.g., pole-pull) and /ul-ʊl/ (e.g., pool-pull) using durational cues, but listeners from Vermont could not (Wade, 2017).…”

“…Another segment that has been shown to have a strong coarticulatory influence on the preceding vowel is dark coda /l/ (Recasens, 2002;Cox & Palethorpe, 2007). Unlike nasals, coda /l/ affects cues that are contrastive in the English vowel inventory, as it reduces spectral cues to vowel contrast (Palethorpe & Cox, 2003;Szalay, Benders, Cox, Palethorpe, & Proctor, 2021;Wade, 2017). For instance, in Australian English, acoustic vowel contrast is reduced in the prelateral context, in particular between the vowels /iː-ɪ/ (heel-hill), /ʉː-ʊ/ (fool-full), /aeɔ-ae/ (howl-Hal), and /əʉ-ɔ/ (dole-doll) 1 (Palethorpe & Cox, 2003;Szalay et al, 2021).…”

‘Grandpa’ or ‘opera’? Production and perception of unstressed /a/ and /əʁ/ in German

“…Once spectral cues to a vowel distinction are lost, duration has been frequently shown to play an important role for a perceptual disambiguation (e.g. Labov & Baranowski 2006, Wade 2017. Little is known about the use of duration to distinguish between unstressed /a/ and ["].…”

“…The finding that the vowels were not distinguished by duration is somewhat surprising, given how frequently this acoustic feature is exploited for a distinction in spectral vowel mergers (Labov & Baranowski 2006, Fridland et al 2014, Wade 2017. Duration also plays a role in distinguishing between /a/ and vocalised /a"/ in stressed syllables that do not show any spectral differences due to /"/-vocalisation (Ulbrich & Ulbrich 2007).…”