You can easily edit your system language through the following steps.

Click on your profile picture (this could be blank) in the top right hand corner of the homepage as seen in the red circle below:

Clicking on the picture will reveal a drop down menu. Select Settings.

Then you will be directed to the profile page where you can edit any of the sections, such as your basic information and contact info:

You can also edit your system language preferences at the bottom of this page by clicking on the pencil. Select the language you want from the drop down menu. When you are finished, don't forget to hit Save.

Important: You must log out and log back in with your new username and password. Doing so will also reset the system language preference if you changed it.

Please see the following video for a tutorial on the above steps.