Fig. 5. The frequency of backchannel words across the corpus.

Backchannel words are a foundational element of conversation that occur at an approximate rate of 1000 per hour of speech; listeners deployed them in nearly two-thirds of speaker turns that were five words or longer. “Generic” continuers, such as “uh huh,” may function to signal to speakers that they should keep talking. In contrast, “specific” backchannel words, such as “wow,” may convey context-specific responses such as mirroring a speaker’s emotion while a story is told. This distribution of backchannels reflects English spoken in the United States in 2020.