There is an extension called 'Page Translator 1.0.1'. The Firefox Extension Store's search feature is so broken I can't even find it. (It was removed by Mozilla). I have the extension installed but under about:addons there is no button that takes me to extension's AMO page either; it only opens the developer's personal website. By default, Firefox does not come with translation features. However, you can easily add such a feature by installing an add-on of your choice. Just enter the URL of the website you want to translate, then select the 'Translate From' and 'Translate To' language (i.e Chinese or Russian to English), and click the button. It will open a new window with the URL translated into the selected language. Google translate gadget for firefox. This extension translates entire webpages into a language of your choice with one click. Idea comes from Google Translation Bar for Chrome. Quick Locale Switcher 1.7.4. Allows you to quickly switch to a different language (User Interface, Spell Checker Dictionary and Website content) in your Mozilla.

The Google Chrome browser has better built-in translation options than Firefox. When you visit a site not in English, Google Chrome will offer to translate. Firefox has no such option, but you can quickly translate pages in the browser with the TranslateWebpageAtGoogleadd-on.
With that extension we can add a translate option to the Firefox context menu. Open this page and click on the + Add to Firefox > Install Now buttons to add it to Firefox. When you right-click a page you’ll now find a Translate this Webpage at Google option on the Firefox context menu as below.
Click on that option to open the page in the shot below. There you choose to translate to a variety of alternative languages by clicking the small arrow just to the left of the Translate button. Then click on the Translate button to open the translated page.
You can also translate straight to the website page without opening the page above. Click the Open menu button > Add-ons and scroll down to Translate this Webpage at Google. Press the Options to open the page below.
There replace http://translate.google.com/#auto/en/ with https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=. Then open a page not in English, right-click and select translate this Webpage at Google. That will translate the page to English in one step.
Translate A Web Page Firefox

How To Translate Web Page Firefox
So now you can quickly translate whole website pages in the Firefox browser. TranslateWebpageAtGoogle makes the comprehensive Google resource more accessible to Firefox users.
