If you want to quickly translate a web page or section of a page to your language, the Firefox extension ‘Translate This’ can help you. This restartless add-on uses Google Translate service for translating the web pages and quite easy to use.
After installing the add-on, just click the Translate button in your add-on bar or use the shortcut key Ctrl + Alt + T (default setting) to translate the entire page.
For a section of a page, select the text you want to translate, right click and choose “Translate This – Selection” option.
You can change your language and shortcut key from the configuration window. Right click on the Translate button to bring up the Settings panel and make changes.
You can install Translate This add-on from Firefox add-on repository.