Vowels are by far the best understood units in human sound systems, and are well characterized at the
articulatory, acoustic, and perceptual levels. This has permitted explanations of vowel systems as
structured by perception, and has led to effective substance-based theories. By contrast, stops are far
less thoroughly understood. In this paper we use an articulatory–acoustic model of the vocal tract to
examine stop consonant place in terms of both articulation and formant values. This allows us to locate
each place of articulation in the F1–F2–F3 space, and to demonstrate in ‘‘articulatory nomograms’’ how
formants evolve while closure is displaced from the front to the back of the vocal tract. Then, in the
framework of the ‘‘Perception for Action Control Theory’’ that we have developed in recent years, we
show that the near universal labial–coronal–velar stop series (i.e., /b d c/ or /p t k/) is a perceptually
optimal structure for stops just as /i a u/ is for vowels, provided that it is embedded in a suitable
perceptuo-motor framework.