What do people do with sniffs, lip-smacks, grunts, moans, sighs, whistles, and clicks, where these are not part of their language's phonetic inventory? They use them, we shall show, as irreplaceable elements in performing all kinds of actions-from managing the structural flow of interaction to indexing states of mind and much more besides. In this introductory essay we outline the phonetic and embodied interactional underpinnings of language and argue that greater attention should be paid to its nonlexical elements. Data are in English and Estonian. Sounds in interaction In spoken and embodied interaction, participants may produce sounds that are not words in the traditional sense but that nonetheless are treated by participants as meaningful. Examples from English in regular orthography include ugh, mmm, argh!, pfft!, brrr (used in English to mark "cold"), and phew. There are many others that cannot be written orthographically, such as clicks, sniffs, or sighs, or items that are made up ad hoc-singular items (Enfield, 2009) whose meaning has to be deduced from the occasion of use. Although items like these are embedded within a linguistic context, linguists do not normally think of them as linguistic objects: They do not belong to a major syntactic category, they may not conform to the phonological requirements of the language, and the relationship between their form and meaning might not be arbitrary, which to a large extent has been considered the sine qua non of linguistic forms (see, however, Dingemanse, 2018). These sounds are therefore at the boundary of language and paralanguage, or nonlanguage. An early sociological account for the use of sounds beyond the lexicon in English was authored by Goffman (1981), who called a group of them response cries and provided impressionistic accounts for their use. Interaction researchers (most notably Gardner, 2002; Goodwin, Goodwin, & Olsher, 2002; Wiggins, 2013) have over the years treated a variety of single examples of sounds with great precision in their embodied context. These results are scattered, not always precise in their phonetic/prosodic detail, and mostly deal with English. Building on the pioneering work on the phonetics of talk-ininteraction (e.g., Couper-Kuhlen & Selting, 1996; Local & Kelly, 1986) as well as the welldocumented embodied turn in interaction research (Nevile, 2015), authors of this special issue take a closer look at a variety of human sounds in natural interaction, aiming to reveal their social organization from a participant perspective.