Slayers Premium (スレイヤーズぷれみあむ Sureiyazu Puremiamu) is the final Slayers movie released in Japan in 2001. In the movie Lina Inverse and Gourry Gabriev travel to the town of Acassi, known for its octopus. However the octopus meat is cursed, causing the person who eats it to only be able to speak takogo (タコ語, octopus language). The people cursed also cannot cast spells.
Gourry just happened to eat one of those octopi, which now caused him to speak in takogo. This often caused very hilarious and awkward situations during the film (the phrase "Great God Almighty" was translated into "Flat Chested", which offended Lina greatly). But soon, everyone in the town began to speak takogo, even though they haven't eaten octopus.
This is the only Slayers movie to feature the characters Lina, Gourry, Ameria, Zelgadis and Xelloss. Naga the Serpent also has a small role, as "the octopus sorceress".
From
Wikipedia