Paste text into the text box and select the language you'd like the text to be translated into.
Alternately, you can enter a website's url and Google will translate the whole site for you. Google currently supports the following languages:
From the site:
English to/from Arabic
English to/from Chinese (Simplified)
English to/from Chinese (Traditional)
English to/from Dutch
English to/from French
English to/from German
English to/from Greek
English to/from Italian
English to/from Korean
English to/from Japanese
English to/from Russian
English to/from Spanish
English to and from Portuguese
Chinese (Simplified) to/from Chinese (Traditional)
German to/from French
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