The sound comes from Duolingo, the language-learning app known for its green owl mascot, Duo. Inside lessons, answering five questions correctly in a row triggers a small celebration, with Duo flapping its wings and a pleasant chime marking the streak. Because millions of learners recognise that moment from their own study sessions, the clip travelled beyond the app and became a familiar shorthand for success in short videos and memes. Creators keep using it because it instantly signals progress, a correct answer or a small win without needing any explanation.