Answer: uhhuh

AnswerCrossword Clue
UHHUHGrunty affirmative
UHHUH"Yup!"
UHHUHSlangy approval
UHHUH"Yeah!"
UHHUH"You bet!"
UHHUHInformal assent
UHHUH"Right"
UHHUHInformal approval
UHHUH"I'm listening"
UHHUHYeah
UHHUHSlangy affirmative
UHHUHSlangy assent
UHHUHGuttural approval
UHHUH"For sure"
UHHUHNodding words
UHHUHClassic John Mellencamp album
UHHUHEquivalent of a pitcher's nod to the catcher
UHHUHAgreement utterance
UHHUH"I'm still listening" comment
UHHUH"Well, go on ..."
UHHUH"Yeah, I guess"
UHHUH"Yes, indeed!"
UHHUHNod's verbal equivalent
UHHUHAffirmative grunt
UHHUHGrunted assent
UHHUH"Sure"
UHHUH"Okay"
UHHUHCompliant sound
UHHUH"Yep"
UHHUH"You betcha!"
UHHUH"I hear you!"
UHHUH"For sure!"
UHHUHAffirmation of sorts
UHHUH"Yup"
UHHUH"I see"
UHHUHGrunted agreement
UHHUH"Yeah"
UHHUH"Yep!"
UHHUHSound of approval
UHHUH"That's correct"