Phonetic variability of stops and flaps in spontaneous and careful speech

Abstract

Variability is perhaps the most notable characteristic of speech, and it is particularly noticeable in spontaneous conversational speech. The current research examines how speakers realize the American English stops /p, k, b, g/ and flaps (ɾ from /t, d/), in casual conversation and in careful speech. Target consonants appear after stressed syllables (e.g., "lobby") or between unstressed syllables (e.g., "humanity"), in one of six segmental/word-boundary environments. This work documents the degree and types of variability listeners encounter and must parse. Findings show greater reduction in connected and spontaneous speech, greater reduction in high frequency phrases (but not within high frequency words), and greater reduction between unstressed syllables than after a stress. Although highly reduced productions of stops and flaps occur often, with approximant-like tokens even in careful speech, reduction does not lead to a large amount of overlap between phonological categories. Approximant-like realizations of expected stops and flaps in some conditions constitute the majority of tokens. This shows that reduced speech is something that listeners encounter, and must perceive, in a large proportion of the speech they hear.

Informativity affects consonant duration and deletion rates

“…However, there is evidence that languages can resist articulatory pressures in their choice of surface realizations. Warner and Tucker (2011) report that the duration of American English /ɡ/ is marginally longer than that of /b/. Ohala (1983) argues that maintaining the voicing of /ɡ/ is more difficult than maintaining the voicing of /b/, which correlates with the higher likelihood of phonemic inventories not to have /ɡ/, compared with their likelihood not to have /b/ (Sherman 1975), and the frequency of the two segments in the world's languages (Maddieson 1984).…”

“…For instance, Zue and Laferriere (1979) studied the distribution of word-medial /t, d/ surfacing as stops and flaps in several phonological environments in American English using word lists, each word embedded in a carrier phrase. Warner and Tucker (2011) compared the articulation of intervocalic oral stops in several phonetic environments and styles of speech, including read speech and phone conversations. Bouavichith and Davidson (2013) focused on intervocalic voiced stops in American English using words that were embedded in short stories.…”

“…Part of the data collected in Warner and Tucker (2011) involves conversations between participants and people they know. This data is crucial for their claim that acoustic reduction is the normal way to communicate by showing that reduction occurs both in casual and in careful speech.…”

Pronunciation Variation in Infant-Directed Speech: Phonetic Reduction of Two Highly Frequent Words

“…First, they occur frequently in both infant-directed and Ernestus, 2000) allemaal is reduced to [ɑməl] in 62.7 % of tokens and helemaal to [heməl] in 20.0% of tokens (Schuppler et al, 2011). Finally, as these words are neither function words nor typical content words, are hardly ever the topic of a conversation and do not refer to a physical entity, their pronunciation is not likely to be affected by predictability or redundancy.We compared infant-directed speech with both adult-directed informal speech and adult-directed read speech, as read speech generally involves more articulatory effort than spontaneous informal speech (Nakamura, Iwano & Furui, 2008;Strik, van Doremalen & Cucchiarini, 2008;Warner & Tucker, 2011). Therefore, if infant-directed speech is characterized by hyperarticulation and clarity, 10 we expect it to be similar to read speech with respect to phonetic reduction.…”

Perception of incompletely neutralized voicing cues in word-final obstruents: The role of differences in production context

“…Moreover, many previous perception studies limited their scope to monosyllabic words ending in coronal stops (e.g., Port and Crawford 1989;van Rooy et al 2003;Warner et al 2004) and relied on small samples of speakers or stimulus items, such as testing 10 or fewer participants and/or stimulus items (e.g., Port and Crawford 1989;Kopkalli 1993;Matsui 2011;Röttger et al 2011). However, the patterns that exist at the level of individual speakers or specific words may not necessarily be representative of group-level behaviors and the entire lexicon, and factors such as word length and consonantal place of articulation are also well-known to play a role in the production of the voicing contrast in obstruents (among others, Gamkrelidze 1975;Ohala 1983;Warner and Tucker 2011). As such, the previously reported cases of the preservation of the voicing contrast in perception do not necessarily indicate that perceptual neutralization is incomplete in the language in general.…”