Multiple Sources of Surprisal Affect Illusory Vowel Epenthesis.

James Whang

doi:10.3389/fpsyg.2021.677571

Abstract

Illusory epenthesis is a phenomenon in which listeners report hearing a vowel between a phonotactically illegal consonant cluster, even in the complete absence of vocalic cues. The present study uses Japanese as a test case and investigates the respective roles of three mechanisms that have been claimed to drive the choice of epenthetic vowel—phonetic minimality, phonotactic predictability, and phonological alternations—and propose that they share the same rational goal of searching for the vowel that minimally alters the original speech signal. Additionally, crucial assumptions regarding phonological knowledge held by previous studies are tested in a series of corpus analyses using the Corpus of Spontaneous Japanese. Results show that all three mechanisms can only partially account for epenthesis patterns observed in language users, and the study concludes by discussing possible ways in which the mechanisms might be integrated.

Highlights

Perceptual epenthesis, is a phenomenon where listeners perceive C1C2 consonant clusters that are phonotactically illegal in their native language as C1VC2 sequences (Dupoux et al, 1999, 2011; Dehaene-Lambertz et al, 2000; Monahan et al, 2009; Durvasula and Kahng, 2015; Whang, 2019; Kilpatrick et al, 2020)
Epenthesizing the shortest vowel in a given language results in an output that is acoustically the most similar to the original signal, is most probable; epenthesizing the vowel with the lowest surprisal in a given context results in an output with total information that is most similar to the original signal, is most probable; epenthesizing the vowel that most frequently alternates with zero in a given context results in an output that is representationally equivalent to the original signal, is most probable
Note that all three mechanisms are triggered by phonotactic violations, which have extremely high surprisal due to their near-zero probabilities, and are repaired by inserting a segment that removes the locus of high surprisal

Summary

Introduction

Perceptual epenthesis, is a phenomenon where listeners perceive C1C2 consonant clusters that are phonotactically illegal in their native language as C1VC2 sequences (Dupoux et al, 1999, 2011; Dehaene-Lambertz et al, 2000; Monahan et al, 2009; Durvasula and Kahng, 2015; Whang, 2019; Kilpatrick et al, 2020). A series of studies by Dupoux et al (1999, 2011) showed that Japanese listeners are unable to distinguish pairs such as [ebzo] and [ebuzo] reliably and exhibit a strong tendency toward perceiving both as [ebuzo]. The current study investigates each in detail and shows that separately the mechanisms can only partially predict human epenthetic behavior and need to be integrated. In order to integrate the three mechanisms, the current study takes a rational approach, reframing illusory epenthesis as an optimization process (Anderson, 1990)

Results

Discussion

Conclusion