Just a thought. But lots of people have said you can change your regional settings to activate Cortana. I wonder if this will be like activating siri on an iphone 4?.
Many people were angry that when siri came out it was only available on the iphone 4s and newer. Essentially the reason for this was that apple wanted everyone to upgrade, and there was no other reason to, they were basically the same phone.
People with jailbroken phones were able to quite merrily install siri and it worked perfectly well showing that there was no physical reason not to allow it.
However whilst siri the app worked perfectly well (as it has when it was a downloadable app in the store, made by someone else), apple had blocked access to the severs to anyone without an iphone 4s or iPad 3, so on an iphone 4 it would just fail to find results.
So i wonder if Cortana would be the same, she would be there but just ignore you?
By the way, even though siri went global at launch, she was only available if you spent another ?500 upgrading early, Cortana may be delayed to all countries, but at least she's free for all, even existing wp8 handsets (ignoring ofcourse wp7, but they are very old, made differently and have a low share these days).
Oh and not only that, but apple also stopped anyone who had previously purchased the siri app from the developer from being able to use it anymore. They all still got over it and bought a new phone. Lol