Is there a Chrome extension that highlights words I've already looked up?

Yes. Echo Translate saves every word you look up and highlights it when it appears again on web pages, in YouTube captions and in PDFs. It's free for Chrome and Edge.

Does it remember words across different websites?

Yes. The word book is shared across every page, video and PDF you read, so a word looked up on one site is highlighted on any other.

Do I need an account?

No. To upgrade to Pro you sign in, and then your word book goes with your account.

Highlight words you've looked up when they show up again

In brief: Echo Translate is a Chrome and Edge extension for people learning English. Every word you look up is saved with the sentence you found it in, and it's highlighted the next time it appears — on another web page, in YouTube captions, or in a PDF. It's for learners who read and watch real English content and want the words they look up to stick, not for translating whole pages.

"I keep looking up the same word and forgetting it"

That's the problem this solves. If a lookup isn't saved anywhere, the word is gone once you close the popup. Echo keeps it:

Look it up where you are. Select or click a word on the page to see what it means in this sentence. The word and its sentence go into your word book.
See it again, highlighted. When it shows up on another page, in a video or a PDF, it's highlighted — including plurals and verb forms (look up address, and addressed lights up too). Hover to remember what it means.
Review it in context. Reviews use the sentence you found the word in, after 1, 3, 7, 15, 30 and 90 days. Meeting the word while reading counts too.

Does it work on any website, or do I have to import the article?

On the page itself. You don't copy, paste or import anything — open the page you were going to read anyway and look up words there.

Does it highlight words in YouTube subtitles?

Yes, for YouTube videos that have CC subtitles. Click any word in the subtitles to look it up, show subtitles in two languages or only the original, and jump back to that second of the video when you review. Videos without CC subtitles aren't supported yet, and the caption tools work on YouTube only (no Netflix subtitles).

What about PDFs?

Online PDFs open right away. For PDFs on your computer, turn on "Allow access to file URLs" in the extension settings once. Files are never uploaded. Scanned PDFs can't be looked up yet.

Is it free?

Yes, with no sign-up:

All the words you look up are highlighted when they come back.
500 word lookups and 20 sentence translations a day.
10 reviews a day. Your word book and reviews cover your 50 most recent words; older words stay saved in your browser.
Import from Kindle Vocabulary Builder or CSV; export to CSV or an Anki file.

Pro ($4.99/month or $35.99/year, or one-time passes) shows and reviews every word, syncs across computers, adds audio review and one-click sending to Anki. → Pricing

Who it's for — and who it isn't for

Good fit: you're learning English, you already read English websites, articles or PDFs, or watch YouTube with captions, and you want looked-up words to come back to you.
Not a fit:
- You're learning a language other than English. Echo is made for learning English (meanings can be shown in 40 native languages).
- You want whole pages translated side by side. Echo translates the words and sentences you pick, not the whole page.
- You study mainly on a phone. Echo runs in Chrome and Edge on a computer (Pro audio review also works on a phone).
- You mostly learn from Netflix subtitles.

What gets sent when I look up a word?

The word and the sentence around it, so the meaning fits that sentence. The page address isn't sent, and PDFs are never uploaded. → Privacy policy

Add to Chrome Add to Edge Added to Chrome Added to Edge Also on Edge Install it on a computer

Echo Translate is an extension for Chrome and Edge, so it can’t be installed on a phone. Open this address on your computer:

echo-translate.com

Sources

Echo Translate facts checked 2026-11-05 PT: lookups and highlights, browsers, review, video, PDFs, languages, free limits, pricing, import and export, data, signing in.