NOTHING: (general sign)
Start with an "O" handshape under your chin, then throw the hand forward and
change it into a loose "5" handshape.
HEARD-NOTHING:
Point at your ear canal with an index finger, then change your handshape into
a "O" and move it forward and down a bit.
KNOW-NOTHING:
Wave a "O" in front of your forehead.
