Web Localiser
This toolbar button changes .com URL domains to a localized URL of your choice, including .co.uk, .fr, .de or .ca. It can be used to find local results in search engines or visit to local versions of a specific site.
Latinka
This extension converts Slavic text (Russian, Polish, Serbian, and other languages) to Slovak and Czech Latin Script.
Translation Window
Hitting Ctrl+Alt+D activates a window with text on foreign websites translated into a language you specify. The extension uses Google Translate.
Franker
Inspired by Ilya Frank's method of language learning, Franker injects the translation directly into the original text. You can read words or sentences in a foreign language first, then check to see if you understood everything. It's designed to help you learn new words and phrases in context. Franker can inject translations for an entire web page or just part of it.
Look Up in SpanishDict 
This extension adds a contextual menu item to perform in-place lookups on SpanishDict.com.
Translate
Translate adds a toolbar item that translates the current web page using Google Translate. You can set the target language and translate in place or view the translation in a new browser tab or window.