The Retarded Letter Game

Howard allowed a caller named Shandor to play a Gary the Retard game. To play, Shandor must guess if Gary knew a word--any word--starting with a given letter. 3 out of 5 takes home a cash prize.

The letters, followed by Shandor's guess and Gary's answers:

"A". Yes. "I don't know! I?"

"M". No. "Man?"

"L." Yes. "L? No."

Fatigued, Howard promised Shandor the cash if he could guess the last answer:

"I". Yes. "I? I don't know!" (which was technically correct, so he won).