People use various gestures while thy speak and listen ; they smile, nod, shake hands, look somewhere and change positions. However humans also communicate without gestures: they precisely understand written texts and dialogues on the radio or on the phone without any forms of gestures at all. This study attempts to respond to a question whether gestures are essential components of linguistic behaviour or they are just supplemental components that can be safely disregarded in verbal communication. We also examine a more aggressive assertions that gestures are critical part of human communication and should be interpreted with verbal language in an holistic and integrated perspective as proposed by Bavelas et al. (2000), Clark (1996) and McNeill (1992, 2005). To tackle the research questions, we built a Korean multimodal corpus composed of audio-visual recordings of verbal communication with rich multi-level linguistic annotations. Using this corpus, we compared verbal backchannels with and without gestures. Through an analysis of these different forms of verbal communications, we explore how gestures influence the interpretation of verbal backchannels. (Yonsei University, Institute of Language and Information Studies)