AxTongue is a free Chrome extension that brings dynamic bilingual cross captions to YouTube videos. Developed by Alex, this extension allows users to view user-submitted "cross captions" directly on the YouTube website.

The main purpose of cross captions is to provide real-time language understanding for viewers who do not speak the language being spoken in the video. With AxTongue, you can immerse yourself in videos in languages you don't understand, without needing to know a single word.

While the extension does not offer all the features available on the AxTongue website or app, such as AI-generated cross captions or the integrated flashcard system, it still provides the core functionality of viewing cross captions. This makes it a valuable tool for language learners and anyone seeking to understand foreign-language videos on YouTube.