Learn languages while reading: translate unknown words and build vocabulary on websites, YouTube subtitles & PDFs. 50+ languages.
Users
220
+85 in 30 days
Rating
4.6 / 5
−0.40 in 30 days
Ratings
5
+2 in 30 days
Store rank
#61K
#51K among extensions
Version
1.3.12
updated 10 Oct 2026
Users
monthly, 13 months
Latest, 15 Oct 2026:220 usersMove the mouse over the chart for any month
Ratings count
monthly, 13 months
Latest, 15 Oct 2026:5 ratingsMove the mouse over the chart for any month
The Chrome Web Store rounds user counts down to the leading digit, so the user line moves in steps. The ratings count is exact and is the better signal of real adoption.
About WordByWord – Vocabulary Builder & Translator
Learn languages while you read. WordByWord turns immersion reading into a system: it shows the words you haven't learned yet, translates them in one click, and tells you — before you start — whether a page or video is at your level.
🌍 IMMERSION READING WHEREVER YOU READ
Unlike apps that lock you into their own content, WordByWord works with the content you already care about:
• Websites and online articles
• YouTube subtitles
• PDFs (local and online files)
• Blogs, news, books, research papers
🔦 SPOTLIGHT MODE — UNKNOWN WORD HIGHLIGHTING
Stop wondering which words deserve your attention. Spotlight instantly reveals the words you haven't learned yet and hides the ones you already know.
• Instantly highlight unknown words on any webpage
• Color-coded by learning status (new → learning → known)
• Update word status directly on the page
• Watch your vocabulary grow over time
📊 COMPREHENSION LEVEL — KNOW IF IT'S AT YOUR LEVEL
Stop guessing whether a video or article is too hard. WordByWord scores it against your own vocabulary before you commit your evening to it.
• A real percentage of words you know — not an average "difficulty" label
• Four clear zones: Easy · Your level · Challenging · Too hard
• The most frequent new words, with a forecast: "These 11 words add +6% understanding"
• Works on YouTube videos (from subtitles), any web article and any PDF
• Learn the short word list, reopen the page — watch the number go up
📺 YOUTUBE LEARNING
• Turn any video into a language lesson
• Click any subtitle word to translate and save it
• Auto-pause on hover
• Navigate by subtitles, not seconds
• See a comprehension score for the video before you play it
📄 PDF TRANSLATOR
• Translate words directly inside the document — a built-in dictionary for any PDF
• Perfect for books, textbooks and research papers
• Works with local and online files
• Coverage is scored page by page as you read
🎯 VOCABULARY TRAINER
• Multiple training modes
• Smart spaced repetition
• Train only the words you actually need
• Review with flashcards
• Import and export your vocabulary (Anki, CSV, PDF)
• See how well you know each word
🌎 50+ LANGUAGES
French, Spanish, German, Japanese, Korean, Italian, Portuguese, Chinese, Arabic, Russian and many more. The comprehension score works in every language you learn — it compares content against your vocabulary, not against English.
💡 HOW PEOPLE USE IT
• Picking a series: score the first episode of three candidates, start with the one in your level
• Filtering a reading list: let the new-words count sort your saved articles
• Getting through a textbook: learn the frequent words first instead of abandoning it at page 20
• Studying with YouTube: click subtitle words, then review them without leaving the browser
🚀 WHY WORDBYWORD?
Unlike basic translators, WordByWord helps you:
✓ See which words you know and which you don't
✓ Know in advance whether content is at your level
✓ Build your vocabulary faster with real content
✓ Track your progress visually
✓ Focus only on the words you still need to learn
✓ Keep learning wherever you read
Free to start — translations, saved words and collections have no limits.
Install → Turn on Spotlight → Grow your vocabulary