Translation in Documents
Translate words or an entire document
With Google Docs, you can translate words within a document, or an entire document, into one of over 40 languages.
Translate a word or a short phrase
A dialog box appears:

The Translate tab displays the selected text at the top, and two language drop-down menus. Select the languages for the translation, and click the Translate button.
Note: Once you get the results, if you click the link with the translated word, you see the reverse translation of that word.
Click the Replace button at the bottom of the dialog box to replace the selection in the document with the translated text.
Translate an entire document
To translate an entire document, simply click Tools > Translate document, and select the language into which you'd like to translate the document.
Google Docs translates the document using Google Translate. Once the translation is ready, you can choose to replace the original document with the translation or create a new document with the translated version.