Segmental and coarticulatory timing in Ikalanga prenasalized stops

The temporal characteristics of prenasalized stops in Ikalanga, a Bantu language of Botswana, are investigated. Eight speakers were recorded producing Ikalanga words with VNCV (NC=/mb nd ŋg), VNV (N=/mnŋ), and VCV (C=/b d g/) sequences. Acoustic measures of 3 speakers’ productions showed that oral closure durations (from vowel offset to closure release) were only slightly longer for NC than for N or C (94, 83, and 83 ms, respectively). When analyzed separately, the N and C portions of VNCV were somewhat shorter than their counterparts in VNV and VCV, but nearly all of the shortening occurred in the C portion (in VNCV, N=78 ms and C closure=16 ms). The durations of vowels preceding the medial consonants did not differ across the three consonant types. Thus, for segmental durations, the main difference between Ikalanga VNCV and VNV was the presence of a brief oral occlusion in the former. However, measures of coarticulatory nasalization point to another systematic difference: while both sequences exhibited comparable anticipatory vowel nasalization, VNV (but not VNCV) sequences showed carryover nasalization extending through more than 70% of the post-nasal vowel. Findings will be compared with previous work on Bantu prenasalized stops. [Work supported by NSF.]