Voices you'll enjoy listening to
Natural pronunciation for words and phrases, with a choice of male or female voice.
The YouTube translator extension that builds your vocabulary
Watch your favorite videos with original subtitles and translate unfamiliar words with a click. Mark how well you know them and track your growing vocabulary.
Laissez la sauce à feu doux pendant vingt minutes, puis incorporez le beurre.
mijoter
From a video you like to words you know
- 01
Turn on WordByWord subtitles
The button is in the player, next to the YouTube controls. Click it once to turn on the subtitles.
- 02
Hover over a word to translate it
Hover over a word to pause the video. Click it to see translation options and hear the pronunciation in a male or female voice. Select several words to translate the whole phrase.
- 03
Save the word with its context
Save a new word with the phrase from the video. Come back to it later in your vocabulary, exercises and flashcards.
Spotlight
See which words are new before they’re said
Turn on Spotlight to color the subtitle line based on your vocabulary: blue for words you haven’t seen before, orange for words you’re learning, and no color for words you already know.
More about SpotlightLaissez la sauce mijoter à feu doux pendant vingt minutes, puis incorporez le beurre.
- Not in your vocabulary
- New
- Recognized
- Familiar
- Learned
- Known
Comprehension
See how much you’ll understand before watching
The percentage next to the subtitle button shows how much of the video’s vocabulary is already familiar. Open the panel to find the most frequent unfamiliar words and see where to start.
How the comprehension score works
Your level
Your sweet spot: you’ll follow the video and pick up new words
1,240words
12new
31learning
Most frequent new words
These 3 words add +2% understanding of this video
mijoter — to simmer×9
incorporer — to fold in×6
éplucher — to peel×4
Replay any line
Replay phrases, not timestamps
Press ← to replay the current phrase or → to move to the next. Repeat along with the speaker without searching the timeline. Adjust the subtitle timing to match the video with Shift + and Shift -.
- ←Previous line
- →Next line
- Shift+Shift-Subtitle timing+0.3s
How this YouTube subtitle translator compares
| YouTube auto-translate | Language Reactor | Trancy | Migaku | WordByWord | |
|---|---|---|---|---|---|
| Translate a word or a whole phrase on click | – | ✓ | ✓ | ✓ | ✓ |
| Word saved with the line it was spoken in | – | ✓ | ✓ | ✓ | ✓ |
| Words colored by how well you know them | – | by frequency | new words | known / new | 5 steps, from new to known |
| Comprehension score before you watch | – | – | – | a score | % and a plan of which words to learn first |
| Videos, websites and PDFs in one vocabulary | – | video, or text you import | video and web pages | web pages only | YouTube, any site, PDF |
| Trainings on the words you saved | – | PhrasePump | exercises | spaced repetition | 8 modes and flashcards |
| Export your vocabulary | – | Anki, CSV | – | Anki | Anki, CSV, PDF |
| Languages you can learn | machine translation | 52 | 10 | 11 | 51 |
Data from the services’ own sites and the Chrome Web Store, September 2026. What Trancy and Migaku offer depends on the language.
Why people keep this YouTube translator installed
50+ languages
From Spanish and Japanese to Icelandic and Swahili — learn several languages in parallel and keep them separate.
Free where it counts
Unlimited translations, audio, flashcards and more.
Your words, exportable
Anki, CSV or printable PDF, any time.
The same extension on everything else you read
Websites
Articles, news, forums: select a word on any page and get the same popup. Spotlight colors the whole page.
Books and papers open in WordByWord’s own viewer, local files included.
Your vocabulary
Every saved word lands in your collections on wordbyword.io: eight trainings, flashcards, export to Anki, CSV or PDF.
Questions about the YouTube translator
Yes. Translating and listening are free and unlimited. A free account adds saving, Spotlight and the comprehension score; Premium lifts the monthly limits on trainings and AI.
Yes. It uses the subtitles the video already has — uploaded by the author or auto-generated by YouTube. If a video has no subtitles in the language you’re learning, there’s nothing to translate, and the extension says so.
No. WordByWord shows one line — the original — and translates the word or phrase you click. That’s deliberate: with a full translation underneath, you read your own language and stop hearing the original.
No. It works on youtube.com, on any website and in PDFs. Netflix isn’t supported.
No. It’s a Chrome extension for desktop browsers. Your saved words live on wordbyword.io, which opens on any device.
50+, from Spanish and Japanese to Icelandic and Swahili. Switch the pair right in the popup. Here is the full list of supported languages.
No. The subtitles and the popup live in an isolated layer over the player. Turn them off with the same button, and YouTube’s own captions come back.
Language Reactor is built around dual subtitles and a side panel. WordByWord keeps the original line, pauses on hover, and turns every saved word into flashcards and trainings with a knowledge level. It works on YouTube, on any site and in PDFs.
Learn a language with videos you love
Install the extension in 10 seconds, translate unfamiliar words with a click, and watch your vocabulary grow.