LingTube

LingTube targets learners who already watch foreign-language video and want study value from that time. Installed from the Chrome Web Store, it runs in the desktop browser and works on YouTube and Netflix. The learner selects a target language and a native language, and from then on subtitles appear as dual lines with colour-coded parts of speech.

The translation layer is the centrepiece. Instead of literal machine translation, LingTube asks a large language model for context-aware renderings of words and phrases, so idioms, phrasal verbs and ambiguous words such as "book a table" are resolved from the surrounding sentence. Words are tagged with part-of-speech information and given CEFR difficulty levels, which lets learners filter vocabulary and plan study paths. For videos without usable captions, an audio transcription pipeline produces high-quality bilingual subtitles.

Study features sit on top of the captions. One click produces a video summary and a structured outline with timestamps, and a chat mode answers questions grounded in the video's content. Learners can pin notes to a specific second and jump back to that moment later, and a shadowing mode lets them repeat a line and compare pronunciation. A separate review area keeps track of saved words and sentences. The interface and target-language support covers majors such as English, French, Spanish, German, Japanese, Korean, Italian and Chinese, with many more native/interface languages. Usage is freemium with paid subscription tiers, and the extension is desktop-only.