NeonLingo

NeonLingo lives inside your browser and helps you learn a language while you read. It is a browser plugin for language learning and translation that automatically highlights words on web pages and lets you look up interpretations without leaving the page.

The free version uses the Microsoft translation engine, supports multiple languages, translates and highlights PDFs, and includes basic flashcards.

The vocabulary list holds up to 200 words, with up to 200 extra interpretations per month.

Paid plans change the limits more than the idea.

Pre costs $5 a month and adds DeepL and AI translation engines, word phonetic transcription, up to 1000 lookups per month, and a 500-word vocabulary list.

It also brings cloud sync for your list, customizable highlight colors, and flashcards built on the FSRS spaced repetition algorithm that work on any device.

Pre+ costs $10 a month and removes the caps on saved words and monthly interpretations, and it adds high-priority responses from the technical team.

If you only read casually, the free tier may be enough.

Heavy readers will hit the 200-word ceiling quickly.