Incipient tonogenesis in Phnom Penh Khmer: Acoustic and perceptual studies

• Documents the emergence of f0-based contrast in Khmer, a non-tonal language.
• Demonstrates the use of multiple acoustic cues in perception and production.
• Proposes a perceptually motivated account of this incipient tonogensis.
• Discusses findings in typological and historical context.

Unlike many languages of Southeast Asia, Khmer (Cambodian) is not a tone language. However, in the colloquial speech of the capital Phnom Penh, /r/ is lost in onsets, reportedly supplanted by a range of other acoustic cues such as aspiration, a falling- or low-rising f0 contour, breathy voice quality, and in some cases diphthongization, e.g. /krɑː/ ‘poor’>[kɑ], [khɔˇɑ], [kɔ¨ɑ¨], /kruː/  ‘teacher’>[ku`ː], [khuˇː], [ku¨ː]. This paper presents the results of production and perception studies designed to shed light on this unusual sound change. Acoustic evidence shows that colloquial /CrV/ forms differ from reading pronunciation forms in terms of VOT, f0, and spectral balance measures, while a pair of perceptual studies demonstrate that f0 is a sufficient cue for listeners to distinguish underlying /CrV/-initial from /CV/-initial forms, but that F1 is not. I suggest that this sound change may have arisen via the perceptual reanalysis of changes in spectral balance, coupled with the coarticulatory influence of the dorsal gesture for /r/.