Whenever you receive message in foreign language in Gmail you don’t need to visit Google Translate page to translate the message instead you can simple enable “Message Translation” labs feature in Gmail to let Gmail automatically detect and prompt for translation of messages.
Translate messages in Gmail
1.Click Settings, click Labs tab
2.Enable Message Translation feature.
3.click “Save changes”.
From now on Gmail will auto detect the language of message and shows on the message header “translate message” link for translation if the message is not in your default language specified in Gmail settings.
After clicking Translate message link your message will be translated inline without opening new tab or new window.