A man walks into his doctor's office and puts a note on the table for the doctor to read. It said, "I can't talk!
The doctor nodded sagely, and instructed the man to put his thumb on the table. The man thinks to himself that his thumb has nothing to do with his inability to talk, but he does as the doctor ordered.
The doctor quickly picked up a big book and whacks the man's thumb with it as hard as he could.
"AAAAAAAAAAAAAA!!!" the man yelled.
"Good, good," the doctor said. "Come back tomorrow and we'll work on the 'B'."