Ray Birdwhistell was an anthropologist who founded the field of kinesics, the study of body movements. In his influential Kinesics and Context, he argues that human communication is more than just the verbal aspect of it:
We cannot investigate communication by isolating and measuring one channel, the acoustic. Communication, upon investigation, appears to be a system which makes use of the channels of all of the sensory modalities. By this model, communication is a continuous process utilizing the various channels and the combinations of them as appropriate to the particular situation. If we think of Channel 1 as being the audio-acoustic (vocal) channel, Channel 2 as the kinesthetic-visual channel, Channel 3 would be the odor-producing-olfactory channel, Channel 4 would be the tactile and so on. Thus, while no single channel is in constant use, one or more channels are always in operation. Communication is the term which I apply to this continuous process.
The channels act to provide redundancy, to reinforce each other, and to provide additional context and depth:
Redundancy makes the contents of messages available to a greater portion of the population than would be possible if only one modality were utilized to teach, learn, store, transmit, or structure experience. Multichannel reinforcement makes it possible for a far wider range within the population to become part of and to contribute to the conventional understandings of the community than if we were a species with only a single-channel lexical storehouse.
Birdwhistell developed a system of kinegraphs to annotate body movements captured in the interviews he had filmed.
Transcribed interviews would look like this: