InterSub
Browser extension for dual-language subtitles and word translations on video.
Pricing
About InterSub
InterSub is a browser extension for Chrome, Edge, and Firefox that adds dual-language subtitles to video content for language learners. It shows subtitles in a person's target language alongside their native language at the same time, and if a video's subtitles aren't available in the chosen language, InterSub can translate them automatically. Hovering over any word in the subtitles brings up an AI-generated definition and translation in context, and looked-up words are saved automatically to a personal vocabulary list for later review. The extension also detects collocations like phrasal verbs, idioms, and compound nouns rather than translating word by word, and it offers a "pause-triggered" mode that hides subtitles during playback and shows them only when the video is paused, aimed at more immersive viewing. A remote-control feature lets a phone be used to look up words while watching on a larger screen, and vocabulary can sync with Anki or a Telegram bot for spaced-repetition review. It works across more than 30 languages and on platforms including YouTube, Netflix, Prime Video, HBO Max, Crunchyroll, Coursera, Udemy, LinkedIn Learning, and TED. InterSub Inc. is based in New York and offers a free installation with pay-as-you-go paid plans and a free trial. Because translations are AI-generated, they may occasionally be imprecise for slang or highly idiomatic phrasing.
At a glance
- Company
- InterSub Inc.
- Platforms
- Chrome Extension
- Integrations
- Anki, Telegram
- Last verified
- August 2026
Who It's For
- •Language learners of all levels.
- •Students and educators in language courses.
- •Bilingual content consumers.
- •Global user base interested in language immersion.
How It Works
- 1Provides dual subtitles for videos on supported platforms.
- 2Offers instant translations and vocabulary tracking features.
- 3Integrates with streaming services for real-time language learning.
- 4Allows personal customization and mobile access for learning on the go.
How to Use InterSub
- 1Install the InterSub extension or app.
- 2Open supported streaming platforms like YouTube or Netflix.
- 3Activate dual subtitles for the video you want to watch.
- 4Use the interface to translate words or track vocabulary as needed.
Key Features
- •Dual-language subtitles
- •Instant hover word translation
- •Automatic vocabulary list (wordbook)
- •Collocation and idiom detection
- •Pause-triggered subtitle mode
- •Anki and Telegram sync
Use Cases
- •Learning a language while watching streaming shows
- •Building vocabulary from video content
- •Studying with paused, distraction-free subtitles
- •Reviewing new words via spaced repetition
Pros & Cons
Advantages
- •Seamless integration with major streaming platforms.
- •Interactive features that enhance vocabulary learning.
- •Supports multiple languages and customization.
- •Improves comprehension through dual subtitles.
Disadvantages
- •Limited information on specific supported platforms.
- •Potential need for browser extensions or app installation.
- •Details about pricing or subscription models are not clear.
Alternatives
- Language Reactor
- Migaku
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Frequently Asked Questions
What is InterSub?
InterSub is a browser extension for Chrome, Edge, and Firefox that adds dual-language subtitles to video content for language learners. It shows subtitles in a person's target language alongside their native language at the same time, and if a video's subtitles aren't available in the chosen language, InterSub can translate them automatically.
How much does InterSub cost?
InterSub is free to use.
Is InterSub free?
Yes, InterSub offers a free plan you can start with.
What are the best InterSub alternatives?
Popular InterSub alternatives include Language Reactor, Migaku.
What is InterSub used for?
InterSub is commonly used for Learning a language while watching streaming shows, Building vocabulary from video content, Studying with paused, distraction-free subtitles.
What platforms does InterSub support?
InterSub is available on Chrome Extension.
Information Accuracy
Please note: While we regularly update all tool information including descriptions, features, pricing, and other details, this information may change over time as tools evolve and update their offerings. For the most current and accurate information, we recommend visiting the official website directly. Our goal is to provide you with comprehensive and up-to-date information to help you make informed decisions.