Ah! Now I see what your original question was about! (But you were missing the word ɲi in your original example )
I have transcribed part of the recording (in case the above link goes dead later).
The context is a female friend sending a voice message in response to a suggestion or request that you all speak in Bambara (or something like that); I have flagged the word that you originally wrote as “nɔ” as o here because that is my best guess as the candidate word that I already know of:
O ɲɛna. I b’à fɛ ka kuma bamanankan de la? O ka ɲi o. O ka ɲi o. Bamanankan ka ɲi o.
It’s clear that you friend is saying O ka ɲi, etc. And yes, then there is something that trails the word before the end of her utterance. As you suggest it seems to be a word for some kind of emphasis, but which?
I think that it is possible that it’s a use of a French loanword non (‘no’, used to mean something like, “right?” in English), but the more likely candidate is o (sometimes written wo) as a particle (in other languages they are called “modal particles”).
O (or ó with a high tone) is a modal particle that is in the dictionary and generally appears at the end of a sentence:
In Bamadaba, it is listed as a particle that expresses “empathy”.
In the use case that you’ve flagged (which is something that I have also heard many times from Bambara speakers, but never thought to investigate ), I think that we are potentially hearing o, but that it is influenced in speaking the preceding sounds ɲi (which is considered nasalized [e.g., ɲin] in other spelling systems like N’ko) and therefore sound like no.
In any case, that’s my best guess for now! I could reach out to other linguists, researchers or experts at some point and ask…or maybe one of them will join this forum!
Let me know if that helps!
Otherwise, what is sure is that my explanation about the postposition nɔ above stands and that it is a completely different word and usage than this instance of O ka ɲi o.