SPELL:Understand

Syntax: cast 'understand' <victim>

Both of these spells change what languages a player may understand.
TONGUES allows the player to talk to any character, regardless of the
languages that they both know.  TONGUES is unidirectional, and does not
allow the victim to understand anyone any better.
UNDERSTAND allows the victim to understand any language, yet does not allow
the victim to speak any better.