[...] it is generally true in Tubatulabal that voiced stops and affricates occurr only in intersonantic, syllabic-initial position, and it is clear that we are dealing with a case of positional alternation: the substitution of voiceless for corresponding voiced takes place in those positions where voiced stops do not (one may say, cannot) occurr.
- Swadesh & Voegelin (2004), Pag. 13-14