A phonetic study of Swahili voiced stops

Despite a rich history of general linguistic research, discrepancy exists within the literature on the phonetic description of voiced stops in Swahili. Polome (1967) reports the voiced stops are phonemically implosive, with plosive allophones in some environments, but which may be strictly egressive for some speakers. Additionally, he states that other speakers have implosives for all stops (i.e., [ɓ], [ɗ], [ɟ]) except the voiced velar plosive [g]. Contemporary descriptions classify all the voiced stops as pulmonic voiced plosives (Mohamed, 2001). This study is an acoustical examination of voiced stops of Swahili speakers from various regions of Tanzania and Kenya to determine the presence of implosives in Swahili and its dialects. The parameters under observation include: (1) voicing onset time (VOT), (2) voicing terminating time (VTT), (3) amplitude, and (4) closure duration as described in several works (Nihalani, 1986; Clements and Osu, 2002; Chávez-Péon, 2005; especially, Cun, 2009). This study discusses preliminary findings on the analysis of five speakers’ productions. Four speakers were found to have implosives in all cases except prenasalized voiced stops. One speaker produced plosives in all instances. The results suggest that variation does occur and further research is needed to establish a better description of the language.