Google Translate

The official Google Translate extension is fine for translating a highlighted word or sentence. Highlight text, or right-click it, and a Translate icon shows the translation. You can change the options so it appears every time you select text. For non-Latin scripts it shows a romanised version, and it supports Cantonese with a listen button. It is published by Google Ireland and has about 39 million Chrome users.

It is narrower than it used to be. The listing says page translation is now built into Chrome and is no longer supported in the extension, so for a full page you use Chrome's own tool, which relies on Google Translate. This extension is now a selection-only lookup tool, and anyone who wants more should look at the other picks.

Your text is sent to Google, and by installing it you agree to Google's Terms and Privacy Policy. The listing says the developer handles location, user activity and website content, and declares that the data is not sold to third parties outside approved use cases. The store rating is a low 3.0 from roughly 44,900 ratings. It is closed source and free, with a short permission list. We found no Firefox listing. Good enough for quick lookups in Chrome.