In
phonetics, this means that the
flow of
air is driven by the
lungs: that is almost all sounds in almost all languages. In theory it is possible to make sounds by
sucking air into the lungs, but such sounds never occur in normal language, and the pulmonic air-stream
mechanism is always
egressive, that is outward-bound.
But there are sounds, the ejectives, implosives, and clicks (qq.v. for details and examples), where the flow of air making the sound comes from a temporary blockage in the throat or mouth, temporarily constricted to cause a pressure differential across the blockage.