Timing lag matters in native speakers' perception of Georgian stop sequences

This study tests the hypothesis that timing lag is part of phonological knowledge, investigating Georgian speakers’ perceptual recoverability of C1 consonantal gestures in stop-stop sequences. We hypothesize that the recovery of C1 is facilitated by (i) longer timing lag (i.e., reduced gestural overlap) between C1 and C2, and (ii) the presence of a C1 vocalic release. Two perception experiments (a forced choice identification and a follow-up transcription task) were conducted using stimuli that have been acoustically and articulatorily analyzed. We consider three acoustic parameters (acoustic lag, presence of C1 vocalic releases, vocalic release duration) and three articulatory parameters derived from EMA data (release lag, onset lag, relative overlap). The results show that longer timing lag does facilitate the accurate recovery of C1, but the presence or longer duration of a C1 vocalic release does not. The results support the inclusion of timing lag in the phonological grammar. We discuss why vocalic releases provide less reliable perceptual information that is potentially ambiguous between segmental and prosodic (syllabic) levels of structure.