Stress oppositions between words like import ≠ import are audible in the nucleus of intonation contours where they are distinguished by fundamental frequency. In the post-nuclear position the opposition is neutralized; the two stresses are identical in terms of fundamental frequency, but measurably different in terms of intensity and duration. Listeners’ reactions are not random, though: those syllables which fit into a regular sequence of stressed and unstressed syllables are interpreted as stressed and unstressed, respectively. Speech production is also influenced by sentence rhythm: syllables which correspond to the general rhythmic pattern have greater duration and intensity. But listeners do not perceive these modificati