Landmark Theory

A theoretical framework in speech science developed by Kenneth N. Stevens proposing that listeners extract phonetic information from acoustically abrupt events called landmarks in the speech signal. Landmarks mark points of rapid spectral change — such as the release of a stop consonant or the onset of voicing — and serve as anchor points around which distinctive features are identified. In assistive technology applications, landmark-based analysis enables systems to detect and classify speech sounds in real time, supporting tools for speech therapy and communication assessment.