Uttering word of chaos creates two effects:
On the caster's home plane, non-chaotic extraplanar creatures within the area are instantly banished back to their home planes. Creatures so banished cannot return for at least one day. This effect takes place regardless of whether the creatures hear the word of chaos.
Creatures native to the caster's plane who hear the word of chaos and are not chaotic suffer ill effects which include confusion, deafness, becoming stunned, or even death.