Perception of glottalization and phrase-final creak

American English has several linguistic sources of creaky voice. Two common sources are /t/-glottalization (where /t/ is produced as a glottal stop and/or with creaky voice, as in "button") and phrase-final creak. Both /t/-glottalization and phrase-final creak have similar acoustic properties, but they can co-occur in English. The goal of this study is to determine whether /t/-glottalization and phrase-final creak are perceived distinctly. Sixteen English listeners were asked to identify words in a two-alternative forced choice task. The auditory targets were (near-) minimal pairs, in which one word could have /t/-glottalization (e.g., "button") but the other could not (e.g., "bun"). Stimuli were presented with and without phrase-final creak. Listeners made few identification errors overall, even when /t/-glottalization co-occurred with phrase-final creak, suggesting that /t/-glottalization and phrase-final creak remain perceptually distinct to English listeners. This supports the view that creaky voice is not a single category, but one comprised of distinct voice qualities.