Stress Effects on Stop Bursts in Five Languages

This study examines the effects of stress on the stop burst in five languages differing in number of places of articulation, as reflected in burst duration, spectral centre of gravity, and ­spectral standard deviation. The languages studied are English (three places of articulation /p t k/), the Indonesian language Makasar (four places /p t c k/), and the Central Australian languages ­Pitjantjatjara, Warlpiri (both five places /p t ʈ c k/), and Arrernte (six places /p t t ʈ c k/). We find that languages differ in how they manifest stress on the consonant, with Makasar not ­showing any effect of stress at all, and Warlpiri showing an effect on burst duration, but not on the ­spectral measures. For the other languages, the velar /k/ has a “darker” quality (i.e., lower spectral centre of gravity), and/or a less diffuse spectrum (i.e., lower standard deviation) under stress; while the alveolar /t/ has a “lighter” quality under stress. In addition, the dental /t/ has a more diffuse spectrum under stress. We suggest that this involves enhancement of the features [grave] and [diffuse] under stress, with velars being [+grave] and [–diffuse], alveolars being [–grave], and dentals being [+diffuse]. We discuss the various possible spectral effects of enhancement of these features. Finally, in the languages with five or six places of articulation, the stop burst is longer only for the palatal /c/ and the velar /k/, which have intrinsically long burst durations, and not for the anterior coronals /t t ʈ/, which have intrinsically short burst durations. We suggest that in these systems, [burst duration] is a feature that separates these two groups of consonants.