Started out of the Bed-Stuy, Brooklyn community and brought to the forefront by rapper Nine11Kevin aka Kevin Madison. A greeting like saying "Wassup" with the sound of the word "Boi" spelled B.A.I.I. meaning (Brooklyn Always In It) since Brooklyn is everywhere and pronounced like "Bye" or "Buy".
What Up Baii? I Aint Seen You In Mad Long baiiiii!
What Up Baii? Wus shakin wit da makin?
What Up Baii? Wassup Wit Da Wassup?
They Spelled It Bai... Betta Go & Get Dat I.. BAII*