Constraints on the Transfer of Perceptual Learning in Accented Speech

Abstract

The perception of speech sounds can be re-tuned through a mechanism of lexically driven perceptual learning after exposure to instances of atypical speech production. This study asked whether this re-tuning is sensitive to the position of the atypical sound within the word. We investigated perceptual learning using English voiced stop consonants, which are commonly devoiced in word-final position by Dutch learners of English. After exposure to a Dutch learner’s productions of devoiced stops in word-final position (but not in any other positions), British English (BE) listeners showed evidence of perceptual learning in a subsequent cross-modal priming task, where auditory primes with devoiced final stops (e.g., “seed”, pronounced [si:th]), facilitated recognition of visual targets with voiced final stops (e.g., SEED). In Experiment 1, this learning effect generalized to test pairs where the critical contrast was in word-initial position, e.g., auditory primes such as “town” facilitated recognition of visual targets like DOWN. Control listeners, who had not heard any stops by the speaker during exposure, showed no learning effects. The generalization to word-initial position did not occur when participants had also heard correctly voiced, word-initial stops during exposure (Experiment 2), and when the speaker was a native BE speaker who mimicked the word-final devoicing (Experiment 3). The readiness of the perceptual system to generalize a previously learned adjustment to other positions within the word thus appears to be modulated by distributional properties of the speech input, as well as by the perceived sociophonetic characteristics of the speaker. The results suggest that the transfer of pre-lexical perceptual adjustments that occur through lexically driven learning can be affected by a combination of acoustic, phonological, and sociophonetic factors.

The VOT Category Boundary in Word-Initial Stops: Counter-Evidence Against Rate Normalization in English Spontaneous Speech

“…Since Norris et al's (2003) influential work, several studies have shown that perceptual category boundary locations for segmental contrasts are affected by ambiguous sounds when the ambiguous sounds are recognized by the listener as a part of a legitimate word (Clarke & Luce, 2005;Eisner et al, 2013;Kraljic & Samuel, 2005;Maye et al, 2008).…”

“…If so, then position and/or context-sensitive representations of phonemes (Dahan & Mead, 2010;Eisner et al, 2013;Mitterer et al, 2013) would predict more distinct phonetic representations of contrasts in positions and contexts where segments are less predictable, and word-specific phonetic representations (Bybee, 2000;Johnson, 2004;Klatt, 1979;Pierrehumbert, 2002;Wedel, 2006) would predict more distinct phonetic representations of less predictable words.…”

A cross-dialectal acoustic comparison of vowels in Northern and Southern British English

“…67-78). 1 Despite the frequent use of SSBE in recent research on speech perception (e.g., Faulkner et al, 2012;Eisner et al, 2013) and the existence of non-acoustic impressionistic descriptions of this variety (e.g., McMahon, 2002), there are no comprehensive acoustic descriptions of the vowels in its vowel system. Perhaps the most complete acoustic descriptions are Deterding (1997) and De Jong et al (2007), but none of these includes all 11 monophthongs or any of the five diphthongs that are recognized in McMahon's (2002) non-acoustic description.…”

The invariance problem in the acquisition of non-native phonetic contrasts: From instances to categories

“…As listeners encounter foreign-accented speech, established lexical knowledge can inform them of a poor mapping from the acoustic signal to native phonetic categories and elicit adjustments in the sound-to-category mappings (Eisner, Melinger & Weber, 2013;Reinisch & Holt, 2014;Sumner, 2011). For instance, a French-accented /p/ sound is acoustically more similar to a /b/ than a /p/ when mapped onto distributions of native English.…”

“…Of note, even amidst multiple nonstandard cues in accented speech, listeners can still accurately track the specific variation tagged to a nonstandard phoneme, suggesting that listeners adjust to the specific qualities that make the phoneme nonstandard (e. g., Reinisch & Holt, 2014;Eisner et al, 2013). Variability in production, per se, does not seem to be an obstacle to adaptation.…”