How to Set your Preferred Language
To set or change the application language, click on the Email shown at the right top and, on the displayed menu, hit Control Panel as illustrated below.
Once there, go to Account Preferences and click on Account Information.
Now choose your preferred language as shown in the following image, and click Save. Remember that for the moment languages available are English and Spanish.
There you go. Now you can change your preferred language as many times as you want!