The only place I see anything language-related is under My Settings > Personal. It's listed as Location for me but says en_US rather than an actual location. If you're seeing a mix of Spanish and English, and it's coming from the site itself and not the browser, it would help to know where you see this and what is in each language. You can upload screenshots directly to this thread.
The username on this site matches the username on other EA platforms, for example the EA App. If you want to change it, go to ea.com, sign in, open Account Settings > About Me, and pick a new name.
