Subtext. From NextFive per NextFive

Learn a new language passively while you browse. Subtext picks some useful words on the webpage for you to practice in your target language. And you immediately see the context.

Instead of grinding through generic language apps, learn vocabulary naturally while reading the articles, news, and blogs you already love.

🌟 Key Features:
• Passive language learning: Almost by osmosis. Open any webpage. The AI will pick useful words and inject corresponding vocabulary in your target language directly into the text alongside original words.
• Interactive Side Panel: Click any injected word (or right-click any text) to open the Deep Dive Sidebar. See nuance meters for translations (Casual vs. Formal), literal meanings, and alternative translations.
• AI Tutor Chat: Don't understand a grammar rule? Ask the AI Tutor directly in the sidebar. It remembers the exact sentence you are reading to give you perfect contextual advice.
• Smart Flashcards (SRS): Save any word or phrase to your personal Deck. Review them using built-in Spaced Repetition logic (Anki-style) so you never forget what you've learned.
• Global Languages Supported: Learn Kannada, Hindi, Spanish, Japanese, French, Arabic, and dozens more.
• Bring Your Own Key (BYOK): 100% free to use. Just paste your own free Google Gemini API key into the settings.

🔒 Privacy First:
Your API key and vocabulary deck are stored locally on your device. Webpage text is only sent to the Gemini API when you explicitly click "Scan" or "Analyze." No personal data is tracked or sold.