Voki is a technology that allows users to create personalized avatars. Users can customize their avatar's appearance and voice, and use their avatar to record and share audio messages in various languages. The document discusses how Voki works and provides examples of its applications in ESL classrooms for activities like vocabulary learning, grammar exercises, and science projects. It notes both the ease of use of Voki and some technical difficulties, and concludes that Voki is best suited for oral skills practice rather than lectures.