High Tone Replacing and Spreading in Kshafa
Overview of the system
Kshafa has a tone system which distinguishes 2 phonemic tones - /+h/ and /-h/, that phonetically surface as a three-level tone system with [H], [M], and [L].
/+h/ usually surfaces as [H], but as [M] when word-initially not before another tone. /-h/ surfaces as [L] after voiced obstruents, and as [M] elsewhere.
ogà /ò.gà/ [ō.gà] "mango"
hikin /híkín/ [hī.kīn] "meat (as food) (nom)"
hikío /hí.kí.ò/ [hī.kí.ō] "meat (as food) (acc)"
The basic mechanism is that when there is an /+h -h +h/ sequence, the first H spreads to the L and either completely merges with the following H to create just a single H, or stays distinct, creating a /+h +h/ sequence.
Replacing and spreading
Word-internally high tone replacing is active, smoothing /+h -h +h/ sequences to just a single /+h/.
hónde /hó.ⁿdè/ [hó.ⁿdē] "they (Sg) will say" + -the /-tʰé/ "present tense marker" => hondethe /hó.ⁿdé.tʰé/ [hō.ⁿdē.tʰē] "they (sg) are saying".
We can see that this is total replacement, because the resulting phonetic melody is [hō.ⁿdē.tʰē] - a flat M all around. If it were a sequence of two /+h +h/, then only the initial vowel would lower, because a word initial /+h/ surfaces as H when before another tone, giving us *[hō.ⁿdé.tʰé]. In cases like this, it might be more accurate call this a morphophonemic change, as opposed to an active phonological process.
Across word boundaries, between words that have a close syntactic relation like between a noun and an adjective that modifies it, high tone spreading is active.
hamî /hà.mî/ [hà.mí] "old (of age)", but when it modifies iflan /í.flán/ [ī.flān] "a crab", the resulting tone sequence is iflan hámî /í.flán há.mî/ [ī.flān há.mí] "an old crab".
We can see that it is merely spreading and not merging, again because of how the initial /+h/ surfaces - [ī.flān há.mí], it is H before the second /+h/, which also surfaces as H because it is not word-initial. If it were tone replacing, the entire sequence would surface with M *[ī.flān hā.mī].
