So far, I've added a whole chapter on sound changes from Common Bantu (a theoretical construct not exactly 1:1 with Proto-Bantu) to Otjiherero, from Möhlig, W. J. G.,
A Reference grammar of Herero, Rüdiger Köppe Verlag, 2008.
Transcribing that, I came into the issue of representing tonal change on the level of the dissylabic stem. What is written on the page:
- H-L Lː-L Hː-L L-L → H-H H-H H-L L-L
Where the tone of the initial syllable and the length of its vocalic nucleus determinate the tone of the last syllable. One solution could be to note the long vowels as two moras independently marked for tone, as the author seems to imply elsewhere in the text:
- H-L LL-L HH-L L-L → H-H H-H H-L L-L
Particularly puzzling are the separate developments LL-L → H-H vs HH → H-L, the first of which being explained by the introduction of a stem-initial respiratory accent delimitating word boundaries, followed by "tone doubling", a phenomenon also responsible for H-L → H-H.
The core of my problem is in how to represent tone on long vowels to explain the different reflexes.