"Little Leroy was starting his" joke

Little Leroy was starting his first day of third grade and the lesson for
that day was to form sentences using Ebonics. The teacher would give each
student a word and they would have to use it in a sentence.
"Leroy?"
"Yea Ms. Johnson"
"Your word is contagious"
"Contagious?"
"Yes Leroy."
Leroy thought long and hard, and finally a sentence came to mind. "Well?",
Miss Johnson said.
Leroy replied "Evry time my mama gets olda, her contagious."