How does an exclamatory greeting tuen into an inquisitory greeting?
Because they're equivalent phrases. Where we would say "Good evening!" as a wish, it's more usual in Swahili to ask, literally, "News of the evening?"
"Good evening, Juma!" may also mean "Jioni Njema Juma!"
it's not making sense
"Habari za jioni, Juma" is used as "How is the evening, Juma."
Exactly so what I am not understanding is the fact that " Habari za jioni, Juma" Means how is the evening but what I am trying to say is. "Good evening Juma". "za" means "is" correct?
No. "Habari za jioni" literally means "News of evening". Za is the plural -a of association. In this case, it means "of".
Is "Jioni njema, Juma" not correct?