gTranslate is a Firefox extension that lets you select text from a web page and translate in another language. For short texts, you can read the translation in Firefox's contextual menu, but in most cases you'll have to click on the short preview to read the full translation. One of the most useful features is replacing the original text with the translation in text boxes. For example, you can write a reply to a post from Google Groups or compose a Blogger post in a language and instantly translate it to another language.
gTranslate uses Google Translate to perform the translations, so it supports the same language pairs.
gTranslate, Firefox, Browser, Extension, Add-on, addon, Lauguage, Tranlator, Open-Source, Open Source