To Google Translate от Juan Escobar

This extension creates a context menu item in Firefox. When you click on this menu item, the previously selected text is sent to Google Translate for translating or to Google TTS for listening pronunciation. You can setup the default languages for translation on the options page.

Privacy Policy: To Google Translate add-on redirects user highlighted text to translate.google.com, including the specified language.

Source code: https://github.com/itsecurityco/to-google-translate