“It is not uncommon for criminals to claim that their deeds were inspired by voices in their heads. One may wonder if deaf psychotics differ from hearing ones in this respect. At least in some cases, it seems that they do. In early 2002, Joseph Mesa … was found guilty of having murdered [two classmates]. Mesa claimed insanity, and that he had been urged to kill by strange voices. These were not literally voices, however, for what he had experienced was signing hands clad in black gloves telling him to commit murder.”

from Limits of Language, an awesome compendium of linguistic Clavinisms