Phonological contrast and phonetic variation : the case of velars in Iwaidja

A field-based ultrasound and acoustic study of Iwaidja, an endangered Australian Aboriginal language, investigates the phonetic identity of nonnasal velar consonants in intervocalic position, where past work has proposed a [+continuant] vs. [−continuant] phonemic contrast. We analyze the putative contrast within a continuous phonetic space, defined by both acoustic and articulatory parameters, and find gradient variation: from more consonantal realizations, such as [ɰ], to more vocalic realizations, such as [a]. The distribution of realizations across lexical items and speakers does not support the proposed phonemic contrast. This case illustrates how lenition that is both phonetically gradient and variable across speakers and words can give the illusion of a contextually restricted phonemic contrast.