Oktarian, spoken on Oktaro, was the original language used by the species known as Oktarians, one of whom was Mayvlin Trillick. The word "Oktar" was used in conjunction with other Oktarian terms to create curse words in the language.
Tom Angleberger's junior novel, The Mighty Chewbacca in the Forest of Fear!, which was released in 2018, was the first time the Oktarian language was showcased.