Chrome extension · YouTube language learning

Learn from real video with dual subtitles

Original captions plus AI translation on YouTube. Click words, repeat sentences, and translate paragraphs on any site. No account — start free instantly or connect your own key.

Add to Chrome See it in action

Install from the Chrome Web Store — start free or bring your own API key.

Free tier OpenAI Anthropic Gemini OpenRouter 10 UI languages Key stays in the browser

YouTube with English captions and Turkish translation

Stay on the video. Learn from it.

Subtitles, dictionary, and translation sit on the player — your API key, your pace.

Sentence-aligned dual captions

Source line plus translation, in lockstep. The source track is picked automatically and can be changed per video.

Click a word, get the gloss

Tap a caption word. IPA, examples, synonyms, and pronunciation without leaving the video.

Sentence repeat

Press S to hear the line again. Optional auto-pause keeps the pace yours.

Translate anywhere

Paragraph (Alt+T) and sentence (Alt+S) — hotkey only.

Four AI providers

OpenAI, Anthropic, Gemini, or OpenRouter. The key never reaches content scripts.

Multilingual UI

Ten languages; follows the browser. Pick target language and models in settings.

Hotkeys under your fingers

Defaults. Change them in Settings — some sites may claim the same shortcuts.

S

Repeat the line

Replay the active caption sentence.

AltW

Word dictionary

Look up the selected word on any site.

AltT

Translate paragraph

Translate the paragraph you are in.

AltS

Translate sentence

Translate the selected or current sentence.

Settings stay out of the way

Provider, model, target language, and hotkeys. Quick switches from the popup.

Demirline settings: provider, model, and language — Provider, model, and target language

Three steps. No Demirline account.

Translation goes to the provider you choose — not to us.

Install

Add Demirline from the Chrome Web Store. YouTube and AI host permissions are listed in the manifest.

Pick provider or key

Start with the built-in free tier or paste your own API key in Settings.

Watch and learn

Open a captioned video. Read both lines, look up words, repeat sentences.

Free for now

Dual subtitles, dictionary, and a 20-entry notebook. Extra plans appear here when checkout is live.

Free

Unlimited dual subtitles, dictionary, and on-page translation. Built-in free tier or your own API key. 20 notebook entries.

Add to Chrome

Later plans

Checkout is not live yet. Paid options will be listed here when they are.

Coming soon