Progressive Immersion is a free browser extension developed by Aidan Welch. Designed to help users immerse themselves in a new language, this extension translates frequent words on the websites you read into a language of your choice using Google Translate.

It's important to note that Progressive Immersion does not aim to teach you a language but rather expand your vocabulary. The extension is open-source and does not track your data. However, it does send selected words to Google Translate for translation, which may pose privacy risks. To mitigate this, you have the option to add websites to the exclusion list or disable the extension before visiting them.

One key feature of Progressive Immersion is that it starts analyzing a page as soon as it begins to load. Therefore, it is recommended to either turn off the extension or add a specific page to the exclusion list before loading it.