Abstract
The terms fortis and lenis are variously regarded as having one single underlying phonetic correlate or many. An exploratory analysis of acoustic and aerodynamic data on contrasting stop series in a number of European and non‐European languages confirms that a significant variation in peak intra‐oral pressure and in articulatory stricture duration are two of the main factors differentiating these series. Two central questions are: (1) Is the contrast in peak pressure controlled by lung volume decrement or by the degree of glottal aperture? (2) Is the gesture for the lenis sound a truncated or a re‐scaled version of the gesture for the fortis sound? A more detailed examination of the data from the non‐European languages suggests that glottal aperture, rather than respiratory effort is the main physiological parameter underlying the pressure variation, and that each member of the opposition has a specific target peak pressure, rather than the lenis peak pressure being truncated by the early release of the articulatory closure.