Predictability modulates pronunciation variants through speech planning effects: A case study on coronal stop realizations

Abstract

Predictability has been shown to be associated with many dimensions of variation in speech, including durational variation and variable omission of segments. However, the mechanism or mechanisms that underlie these effects are still unclear. This paper presents data on a new aspect of predictability in speech, namely how it affects allophonic variation. We examine two coronal stop allophones in English, flap and glottal stop, and find that their relationship with predictability is quite different from what is expected under current theories of probabilistic reduction in speech. Flapping is more likely when the word that follows is more predictable, but is not influenced by the frequency of the word itself, while glottal stops are more likely in words that are less predictable. We propose that the crucial distinction between these two allophones is how they are conditioned by phonological context. This, we argue, interacts with online speech planning processes and gives rise to variability for context-dependent allophones. This hypothesis offers a specific, testable mechanism for certain predictability effects, and has the potential to extend to other factors that contribute to variability in speech.

Physical and phonological causes of coda /t/ glottalization in the mainstream American English of central Ohio

“…If the sonorant effect is considered to be an allophonic alternation, this decrease is consistent with the hypothesis that phonological alternations that depend on upcoming sounds are sensitive to the availability of those sounds during speech production (Côté, 2013;Kilbourn-Ceron, 2017;Kilbourn-Ceron et al, 2020;Kilbourn-Ceron & Sonderegger, 2018;Kilbourn-Ceron, Wagner, & Clayards, 2016;Tanner, Sonderegger, & Wagner, 2017;Wagner, 2012). Because a sonorant is arguably less accessible during planning when it occurs in a new phrase than when it occurs during the existing one, a phonological (planned) sonorant effect should apply slightly less often across phrase junctures than within the same phrase.…”

“…This prediction is supported by the findings in Kilbourn-Ceron et al (2020): Prevocalic coda /t/ glottalization is more likely when the word is lengthened (cf. speech rate in Kaźmierski, 2020), when it is followed by a short pause, or when the following word is relatively unpredictable.…”

“…American English voiceless stops in syllable codas are sometimes pronounced with audible glottal constriction (Bellavance, 2017;Cohn, 1993;Eddington & Channer, 2010;Eddington & Taylor, 2009;Huffman, 2005;Kahn, 1976;Kaźmierski, 2018Kaźmierski, , 2020Kaźmierski, Wojtkowiak, & Baumann, 2016;Kilbourn-Ceron, 2017;Kilbourn-Ceron, Clayards, & Wagner, 2020;Levon, 2006;Pierrehumbert, 1994Pierrehumbert, , 1995Redi & Shattuck-Hufnagel, 2001; Roberts, 2006). For example, the word 'bat' may be pronounced as [baet], [baet], [baeʔt], or [baeʔ].…”

“…American English coda glottalization is also attested in word-final position before vowels, though at much lower rates than before consonants (Eddington & Channer, 2010;Eddington & Taylor, 2009;Kaźmierski, 2018Kaźmierski, , 2020Kaźmierski et al, 2016;Kilbourn-Ceron, 2017;Kilbourn-Ceron et al, 2020;Roberts, 2006;Umeda, 1978). While prevocalic position does not necessarily favor /t/ reduction, glottal stops are often produced before vowel-initial words, especially at phrase junctures and in stressed syllables (Dilley et al, 1996;Garellek, 2013;Pierrehumbert & Talkin, 1991;Umeda, 1978).…”

Prevocalic t-glottaling across word boundaries in Midland American English

“…In the present case, this means a higher chance of flapping, the process expected word-internally, to occur (cf. Kilbourn-Ceron, Clayards, & Wagner, 2020).…”