Read Thread: AQ Site Language Options.
Aprima numero 2 para Español.
Seriously though, there is a negotiation that can occur between your browser and a web site. If there are multiple language versions available on a web site, the browser tells the site which version to send. You probably don't know about it because your browser defaulted to the correct language, English for you. I've set up English as primary, but Spanish is secondary.
Well, most browsers have it, but I can't find the language settings on Chrome on my tablet. Firefox help on my tablet says that language is chosen when I chose which version to download. I'm upgrading my desktop right now so I can't check there, but I've done the above selections there.