Vocabulary Highlighter — Learn Words While You Read

Highlight unknown words on any website. 12 languages. Flashcards, spaced repetition, word frequency. No account needed.

Learn vocabulary in 12 languages by reading websites and watching YouTube — Reddit, Medium, news, documentation, videos, anything. HOW IT WORKS Open any webpage → click "Activate" → every word gets color-coded. Green = you know it. Red = you don't. Click an unknown word, press Enter — it's added to your dictionary. The extension remembers. Over time, you see fewer red words. That's your progress. WORKS ON YOUTUBE TOO (NEW in 0.4.0) Turn on CC subtitles and learn vocabulary while watching videos. Same dictionary across reading and watching — a word you learn on a website won't be highlighted on YouTube and vice versa. CROSS-LANGUAGE VOCABULARY (NEW in 0.4.0) Learning German after English? Words you already know from English (like "system", "problem", "information") are automatically detected and shown in a subtle yellow — so you can focus on truly new words. MULTI-LANGUAGE SUPPORT Learn English, Spanish, French, German, Italian, Portuguese, Russian, Turkish, Arabic, Hindi, Japanese, or Korean. Switch languages instantly from the popup — each language has its own dictionary, stats, and flashcard deck. Translations powered by MyMemory API with Google Translate fallback. ANKI-STYLE FLASHCARDS Words you encounter 50+ times while reading automatically become flashcards. Practice them with Anki-style buttons showing exact intervals: Again (1d) / Good (3d) / Easy (7d). Words graduate to "learned" after multiple successful reviews — no premature deletion. Built-in SM-2 spaced repetition algorithm. WORD FREQUENCY TRACKING See which unknown words appear most often across everything you read. Filter by time period: days, weeks, months, or years. Delete junk words with one click. Focus on high-frequency words first — they give you the biggest reading comprehension boost. QUICK SETUP QUIZ Mark common words you already know in batches of 150. Hover any word to see its translation. Already-known words are pre-selected. Available for English, Spanish, French, German, Italian, and Russian (1,500 words each). CLICK-TO-TRANSLATE Click any word to instantly see its translation or definition. English words get dictionary definitions; other languages get translations to your native language. Google Translate link as fallback. FEATURES - 12 languages with instant switching - Works on websites AND YouTube subtitles - Cross-language word detection (know it from another language? we'll show it) - Anki-style flashcards with SM-2 spaced repetition - Top unknown words ranked by frequency (50+ encounters) - Inline translations and definitions - Quick setup quiz with hover translations (1,500 words per language) - Customizable highlight colors - Import/export word lists (CSV) - Reading streaks, daily stats, and learning charts - Cross-device dictionary sync via Chrome - Smart script detection (Japanese doesn't highlight English text, etc.) PRIVACY No account. No cloud servers. Your dictionary syncs through your Chrome profile — only you can see it. Word lookups use free translation APIs. All highlighting happens in your browser. WHO THIS IS FOR Language learners (intermediate+) who want to build vocabulary from real content instead of textbook word lists. Works best when you read and watch every day — articles, Reddit threads, YouTube videos, documentation, blogs. WHAT'S NEW IN 0.4.0 - YouTube subtitle highlighting — learn while watching - Cross-language vocabulary detection (words known from other languages shown in yellow) - Anki-style flashcard buttons with interval labels (Again/Good/Easy) - Words graduate after 21+ day intervals (no instant deletion) - Smart word filtering: only 50+ encounter words enter flashcards - Learning chart (30-day bar graph) and streak counter on flashcards page - Language selector on flashcards and review pages - Quiz: hover-to-translate and pre-selection of known words - Delete button (✕) to remove junk words from review - YouTube widget reminder to turn on subtitles