That could depend on where you are, and where your carrier enters the internet. A website is in the language it's written in - browsers don't translate them. If the site you got to is written in English, you'll see English (unless you have some kind of add-on in your browser that translates every page). You might be being redirected to Spanish language sites because of your location.
Try using a different browser and see if it still happens. Then you'll know if it's the browser or something outside your phone.