Sam and I spend time every day holding the pups and petting them. Last night as Sam was holding Chili and petting him, he yodeled! It startled both Sam and I since it was totally unexpected. Chili can be very loud but is not usually too vocal. Pep vocalizes frequently but they are quieter sounds. When I hold him he makes quiet happy sounds, he is also vocal when nursing. Sophie is the only one who does not really vocalize.