Excellent question! I had (Ki)Swhili in college long ago (last century) and I remember that Bibi was Madame or Miss ("How are you today Miss Sarah?" = "Habari za leo, Bibi Sarah?"); is that correct? ...just as Bwana is Sir or Mister--as Dalaryn points out--respectful/lordship piece we see in many languages I think, e.g. señor, monsieur (mon seigneur), and Herr, and our mister/master.
"How is the morning, grandmother?" To ask grandmother how she is this morning–or how the weather is this morning ... It's like "How are you doing?" in that it doesn't inherently make much sense, but if you hear it a lot of times in the same general context, you associate a meaning with it.
The sentence in Swahili is a question meaning how is the/your morning grandma? But the only word options Duolingo gives to translate the sentence, that make sense, are good, morning and grandmother.
So you can ask a question without expecting an answer, and the question becomes a declarative sentence?
No one knows which language influenced which... there are a lot of similar words
Bibi Baba Dunia/dunya Chai
As people mirgrated from Africa to - all the other places .. did they bring their language with them and the the languages developed or
Did the language come down when the slave trade came ?
As I am not an athropologists it is difficult to say :)