Noah Webster
Undulate
UN'DULATE,
UN'DULATED, adjective Wavy; waved obtusely up and down, near the margin, as a leaf or corol.
UN'DULATE, verb transitive [Latin undula, a little wave; unda, a wave; Low Latin undulo.]
To move back and forth, or up and down, as waves; to cause to vibrate.
Breath vocalized, that is, vibrated and undulated -
UN'DULATE, verb intransitive To vibrate; to move back and forth; to wave; as undulating air.