Google is constantly trying to improve its products for the end users' sake. Often times Google first puts new features into the Labs section of Google. These Labs are basically beta versions of features they plan to add to existing projects or as brand new projects. Every now and again the more popular labs get promoted to full versions.
Today just happens to be one of those days for one lucky Lab project. There was a Lab that has been around since 2009 that uses Google Translate to translate e-mails in a foreign language to that of the user. It works in a similar manner to the way Google Chrome recognizes foreign language websites and offers to convert them.
A few other more minor tweaks have also been promoted from Labs. These features include a tweak to change the title on the tab of a Gmail page. The tweak places the number of unread e-mails first. Another Lab improves the Mute button's ability to stop you from being harassed by company-wide reply all e-mails. The tweaks are said to be live, so check them out yourselves!