Datapoint Sango/Uses of the habitual marker
I have noticed the occasional use of a postverbal morpheme ka (with low tone) in my recordings of the 1990s. Some speakers use both COP and ka. (I do not have enough data to make generalizations —linguistic and sociolinguistic —about its occurrence.) The earliest examples come from vinyl recordings of dance music (probably the 1970s). Perhaps ka has been adopted from Lingala or Kituba, because a lot of this music was created, it seems, by musicians in Brazzaville.
Values 
Habitual, progressive and future
Frequency: 90.0%
- Example 59-51:
-
nyen' aso mo si mo eke toto tongaso?nyen'whatasosm.hurtmo2sgsithenmo2sgekecoptotocrytongaso?thusWhat ails you that you're crying like this?
- Example 59-146:
-
mo yeke te nyama ti nyen'?mo2sgyekecopteeatnyamameattiofnyen'?whatWhat kind of meat do you (habitually) eat?
- Example 59-147:
-
lo tene mama ti lo ake kiri lawalo3sgtenesaymamamothertioflo3sga-kepm-copkirireturnlawawhenHe asked when her mother was returning.
- Example 59-150:
-
mbi ke leke tere ti mbi ti kirimbi1sgkecoplekefixterebodytiofmbi1sgtitokirireturnI'll prepare myself to return.
Source: Samarin 2001: 136
- Confidence:
- Very certain
Only habitual function
Frequency: 10.0%
- Example 59-152:
-
tongana lo mu samba na ala, ala ken', ala tene, baa ala nyon'ka samba pepetonganawhenlo3sgmugivesambabeernaprepala,2plala2plken',refuseala2pltene,saybaaseeala2plnyon'-kadrink-habsambabeerpepenegWhen he offers you beer, refuse, say, "Look, I don't drink beer."
- Example 59-153:
-
[...], mo teen', baa, mo nyon' samba ape o[...],[...]mo2sgtene,saybaa,seemo2sgnyon'drinksambabeerapenegodef(When he offers you beer), say, "Look, I don't drink beer, thank you."
- Confidence:
- Very certain