p' t' k' q'
contrast with plosives in various languages:
Caucasian, East Asian, American, African
Constraints on gestural timing
Languages differ in the timing of the laryngeal gesture with respect to the oral constriction gesture. Above example like timing found in Hausa (Afro-Asiatic language spoken in Nigeria) and K'ekchi (Mayan language spoken in Guatemala).
Lakhota (Siouan language spoken in North America) shows timing more like that below:
Why are ejectives voiceless?
Can there be glottalic pressure fricatives?