How to change my AppStore and iTunes language to English?

I've always used the appstore on my iPhone in English, as my account is english. But suddenly its not in english anymore, oh no, its in ITALIAN! So now i can't update any of my apps, or download any new ones. And not only that, my itunes store is now completely in italian too. I don't even know how that happened… One week its in english, the next its in italian… And when i try to update anything, it says that my account information is not valid for the italian account, but for the english. I DON'T EVEN HAVE AN ITALIAN ACCOUNT!
i just need to know how to change it back to english because i really need to update my apps. I go to italy often, but this has never happened before, and the last time i went to italy was over a month ago.
thanks in advance:)

Bottom right, click the circle icon that represents the flag of that country where you are located… Or the country where Apple thinks you are located.

You could also trash the preference file at…
and then the next time you open App Store, it will geo-locate you at your current location.