Throughout the morning, I've been having conversations with a community member who updated to Windows Phone 8.1, but Cortana was just not available. After brainstorming ideas, we finally determined that, during one of the three servicing updates (that leads up to the actual Windows Phone 8.1 install), the phone had set the region and language to UK for some reason (he's NOT in the UK).
As has been reported, Cortana is intended to be US-only for now, but a simple trick can enable Cortana's features even for those in Europe. This same trick solved the problem from this morning since the reboot decided to change the country code.
Here's how to change it:
- Go into the Settings menu.
- Change the Region to United States, English (United States).
- Change the Language to English (United States).
The phone will reboot at least once (maybe a couple times in some cases) to install new updates and apply settings. Once it's complete, Cortana will be enabled.