Ainu is a language of Far East Asia historically spoken in the territories of today’s Russia and Japan that face the Southern Okhotsk Sea. Specifically, Ainu was spoken all through the Japanese island of Hokkaidō (also referred to as ‘Ezo/Yezo’ in old sources), in the southern part of Sakhalin island (called ‘Karafuto’ by Japanese people), in the Kuril Islands chain (called ‘Chishima’ by Japanese people), and in the southernmost tip of the Kamchatka peninsula. Although a number of hypotheses about Ainu’s relation to other languages have been proposed (Dougherty 2019, 100), the language is presently classified as an isolate (see Lesson 18). There exist three main varieties of the language, that take their names from the regions where the language was spoken: Hokkaidō Ainu, Sakhalin Ainu, and Kuril Ainu. Both Kuril Ainu and Sakhalin Ainu are extinct, and Hokkaidō Ainu is classified as critically endangered by UNESCO.