Duality means that the way we percieve is discordant to reality, not the same as what is in fact the case. The way it appears is out of harmony with the way it actually exists.
Language
Words of Wisdom
"May all sentient beings have happiness and its causes. May all sentient beings be free of suffering and its causes. May all sentient beings not be separated from sorrowless bliss. May all sentient beings abide in equanimity, free of bias, attachment and anger."