Ejectives
p' t' k' q'
contrast with plosives in various languages:
Caucasian, East Asian, American, African
[baka] [ak'a]
Gestural composition
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?