Articulatory phonetics is concerned with the physical apparatus used to produce speech sounds and the physical and cognitive factors that determine what are possible speech sounds and sound patterns. Given the common understanding that speech articulation is an integrated part of a communication system that also includes speech perception, articulatory phonetics is usually treated within a broader context of the full speech chain, which additionally includes speech aerodynamics, speech acoustics, and speech perception. Consequently, the research reports and reference and teaching tools in the field are dispersed over a wide range of works that treat phonetics more generally. Because of the enormous size of the relevant literature, only more recent or particularly comprehensive earlier works are highlighted here. Key theoretical questions in articulatory phonetics include what units are used in speech planning and which aspects of observed speech movements are learned as part of a particular language rather than being a consequence of how the speech mechanism works (whether this is physical constraints of the actual speech organs or cognitive aspects of speech motor planning and execution). Cross-linguistic investigations of speech sound inventories and articulation have been critical to clarifying this distinction. Another long-standing question is whether and how articulation planning is influenced by knowledge of the acoustic outcome and its importance to maintaining distinctions critical to the perceptual needs of the “listener” as a generic or a specific entity. Discussions of historical sound change have appealed both to organic constraints and to ambiguities in the acoustic-articulatory mapping process as factors that influence the source and path of pronunciation change over time.