Atoan was the language spoken by natives of the planet Atoa. When Imperial forces arrived on Atoa around 19 BBY, they found that the unintelligible natives did not speak Basic, which was an oddity as the nearby planet of Umbara had been involved in the Galactic Republic for thousands of years.
One exception was the shaman Lady Saro, who said she had recently gained the ability to speak Basic by killing a stormtrooper and consuming his tongue.