Online perception of glottalized coda stops in American English

In American English, voiceless codas /t/ and /p/ are often glottalized: They have glottal constriction that results in creaky voice on the preceding vowel. Previous claims suggest that such glottalization can serve to enhance /t/ or, more generally, voicelessness of coda stops. In this study, we examine the timecourse of word recognition to test whether glottalization facilitates the perception of words ending in voiceless /t/ and /p/, which is expected if glottalization is in fact enhancing. Sixty American English listeners participated in an eye-tracking study, where they heard resynthesized glottalized and non-glottalized versions of CVC English words ending in /p, t, b, d/ while looking at a display with two words presented orthographically. Target words were presented with a minimal pair differing in place of articulation (e.g., cop-cot), or voicing, (e.g., bat-bad, cap-cab). Although there is little evidence that glottalization facilitates recognition of words ending in /t/ or /p/, there is a strong inhibitory effect: Words ending in voiced stops are recognized more slowly and poorly when the preceding vowel was glottalized. These findings lend little support to a listener-driven, enhancement-based explanation for the occurrence of coda glottalization in American English. On the other hand, they suggest that glottalized instances of coda /t/ and /p/, but not of coda /d/ and /b/, are perceived as equally good variants of these sounds.