Definition of sputter:
moist matter thrown out in small detached particles; also, confused and hasty speech
to spit, or to emit saliva from the mouth in small, scattered portions, as in rapid speaking
; to utter words hastily and indistinctly; to speak so rapidly as to emit saliva
"they could neither of them speak their rage, and so fell a sputtering at one another, like two roasting apples. -Congreve."