Distinctive features, quantal theory, and enhancement
Helen M. Hanson · The Journal of the Acoustical Society of America · 2015
Ken’s background in physics and engineering and keen interest in phonetics gave him a rare ability to suggest a quantitative basis for distinctive features. His awareness that the acoustic correlate of a smoothly varying articulatory parameter might have a sudden change in value led to his development of Quantal Theory. In addition to providing a basis for distinctive contrasts, it provides a means for a continuous-time signal to reflect the discrete nature of the underlying representation of speech sounds. Later work led to two types of quantal relations: those based on aeromechanical properties of the vocal tract, which lead to manner features, and those based on coupling between cavities, which lead to articulator-bound features. Ken also suggested that each feature has a defining articulatory state, and thus, a defining acoustic correlate. Neighboring segments or higher-level phenomena may threaten the salience of defining acoustic correlates. Enhancement theory was developed to account for the fact that the defining articulatory or acoustic correlates are threatened in some environments. At such times, enhancing gestures that bolster the salience of the defining acoustic correlates are brought into play. Much of the work produced by Ken’s students was aimed at finding support for these theories.