1. used to express disbelief( more effective if lips are pushed out like Arnold from Different Strokes, then the sound is made with the mouth pouted ,closed, and monotone)
2.used as a sound of agreement(same closed mouth as above but the pitch slightly rises o the second syllable)
3.used to show disgust(sam mouth as above,but extremly quick puff out like a dog's sneeze)
2.I told dat trick dat he'ain no good. Friend girl replies,"UMHUM"(2.) Gurl,you ain nevah lyed!
3. Jose!! Mira! Tu bendeho! tu sabes I gotta be da work at 5!!! C'mon man, "UMHUM"(3.) as she slams the door