Voki is a web 2.0 tool that allows users to create personalized avatars that can speak. Users can customize the avatar's appearance and background. The avatar's voice can be recorded by the user or generated through text-to-speech. Voki avatars can be used to improve listening and speaking skills through activities like introductions, role plays, and practicing vocabulary pronunciation. Students enjoy creating their own avatars and listening to the recorded voices. The process involves signing up on the Voki website and creating an avatar.