A man walks into his doctor's office and puts a note on the table. It reads: "I can't talk! Help me!"
The doctor nods sagely and instructs the man to place his thumb on the table. The man thinks his thumb has nothing to do with his inability to speak, but he complies.
The doctor quickly picks up a heavy book and whacks the man's thumb as hard as he can.
"AAAAAAAAAAAAAA!!!" the man yells.
"Good, good," the doctor says. "Come back tomorrow, and we'll work on the 'B'."