Sublern

What is Sublern?

Sublern is a Chrome extension that adds word-by-word subtitle translation to video platforms. It is designed for language learners who want to understand spoken content without pausing the video or leaving the page.

The extension works as an overlay on supported video players, letting users hover over a subtitle word to see its translation, pronunciation, and example sentences. According to the site, it supports platforms such as YouTube, Netflix, TED, Udemy, Twitch, Plex, Jellyfin, and other players that use Video.js, Shaka Player, or Playerjs.

Key Features

• Word-by-word subtitle translation — Hover over a subtitle word to see its meaning in context instead of searching in a separate tab.
• Example sentences from native content — Displays three real-world example sentences so users can see how a word is used.
• Text-to-speech pronunciation — Plays the selected word aloud with a native voice on one click.
• Auto-pause on hover — Pauses the video while a translation is open and resumes when the cursor moves away.
• Customizable interface — Lets users adjust font size, tooltip position, colors, background opacity, and the number of examples shown.
• Dictionary saving and keyboard shortcuts — Users can save words to a personal dictionary and use shortcuts to show or hide subtitles, copy words, or manage examples without the mouse.
• Multi-language support — The interface is available in 20+ languages, and translation supports 30 languages.

How to Use Sublern

Install the Chrome extension from the Chrome Web Store, then open a supported video with subtitles. When you hover over a subtitle word, the extension shows the translation, pronunciation, and examples directly on the video. You can also click to save words to your dictionary or use keyboard shortcuts for faster navigation.

Use Cases

• Watching foreign-language videos for study — Learners can keep up with videos in a target language while checking unfamiliar words in place.
• Learning vocabulary from context — Users can read example sentences alongside the translation to understand usage, not just dictionary meaning.
• Studying with streaming platforms — People watching content on sites like YouTube, Netflix, or TED can look up words without switching apps or tabs.
• Reviewing words later — Learners can save interesting vocabulary to a personal dictionary for later practice.
• Using videos in fullscreen or picture-in-picture — The tooltip is designed to work directly over the video, including fullscreen modes.

FAQ

Which platforms does it support? Sublern supports YouTube, Netflix, TED, Udemy, Rutube, Disney+, Prime Video, Twitch, Plex, Jellyfin, Emby, Kodi, and sites using Video.js, Shaka Player, or Playerjs.

Does it work with auto-generated subtitles? Yes. The site says auto-generated YouTube captions work the same way as manual subtitles.

Does it work in fullscreen mode? Yes. The tooltip overlays the video in fullscreen and picture-in-picture modes.

Does it store viewing data? According to the site, no viewing history is stored or sent to a server controlled by the product.

Is it free? Yes. The site describes Sublern as free, with no account required and no premium tier.

Alternatives

• Traditional dictionary extensions — These usually require opening a new tab or copying text, which makes them less integrated with video playback.
• Subtitle translation websites or apps — These can help with language learning, but they generally sit outside the video player instead of overlaying subtitles in place.
• Built-in platform subtitles and translation tools — Some video services offer captions or translation features, but they may be less interactive or less consistent across sites.
• Vocabulary flashcard tools — These are useful for review after watching, but they do not provide in-player translation or pronunciation while the video is playing.