NeonLingo

NeonLingo is a browser extension that turns everyday web browsing into a language learning environment. Designed for self-directed learners who want to acquire vocabulary through natural reading rather than memorization drills, the extension works with Google Chrome and Microsoft Edge to create immersive language exposure during normal browsing sessions.

How It Works

NeonLingo is built around linguist Stephen Krashen's comprehensible input theory (i+1), which holds that language acquisition happens when learners encounter input slightly above their current competency level. The extension implements two complementary modes. On native-language pages, an AI engine predicts which words the user is ready to learn and replaces them with target-language equivalents, creating a mixed reading experience that blends familiar context with foreign vocabulary. On foreign-language pages, the extension provides on-demand translation and automatically saves looked-up words, turning difficult content into comprehensible input.

Key Features

• Smart word substitution: AI selects vocabulary matching the user's current level and replaces native words with target-language equivalents during everyday browsing.
• Instant selection translation: Selecting any word on a foreign-language page provides an immediate context-aware translation powered by Microsoft, DeepL, or AI translation engines.
• Automatic wordbook and cloud sync: Every looked-up word is saved to a personal vocabulary list that syncs across devices on premium plans.
• Contextual review highlighting: Previously learned words are highlighted when they reappear on any web page to reinforce retention through spaced repetition.
• FSRS-based flashcards: Premium users get flashcards powered by the Free Spaced Repetition Scheduler algorithm, usable across any device.
• Document translation: Users can translate entire documents through the extension interface.

Use Cases

• Self-directed learners: Individuals who want to weave language practice into their daily browsing routine without dedicated study sessions.
• Professionals and developers: People reading technical documentation or industry content in a foreign language who need to build vocabulary naturally.
• Test preparation: Students preparing for language exams who benefit from repeated contextual exposure to vocabulary across real web content.

Pricing

NeonLingo offers a free tier with automatic word highlighting, Microsoft translation, multilingual support, a 200-word vocabulary list, 200 interpretations per month, and basic flashcards. Premium ($6.49/month billed yearly or $12.99/month) adds DeepL and AI translation engines, 500-word vocabulary list, 1000 translations per month, cloud sync, customizable highlighting colors, and FSRS-based flashcards. Premium+ ($12.49/month billed yearly or $24.99/month) removes all usage limits and adds priority technical support. Users can earn free premium through a referral program.

Privacy and Security

NeonLingo processes page content locally for word substitution and translation and collects usage data to personalize vocabulary recommendations. The company reports that it does not sell user data.