Standard models of language and communication depart from the assumption that speakers encode and receive messages individually, while interaction research has shown that utterances are composed jointly (C. Goodwin, 2018), dialogically designed with and for others (Linell, 2009). Furthermore, utterances only achieve their full semantic potential in concrete interactional contexts. This SI investigates various practices of human sounding that achieve their meaning through self and others' ongoing bodily actions. One person may vocalize to enact someone else's ongoing bodily experience, to coordinate with another body, or to convey embodied knowledge about something that is ostensibly only accessible to another's individual body. This illustrates the centrality of distributed action and collaborative agency in communication. © 2023 The Authors