Over the last few Insider builds of Windows 10 Mobile, many users with higher spec'd phones saw the return of Hey Cortana – the hands-free, voice-activated personal assistant. However, for many users, including on our Lumia 1520 we had the feature but could not get it to recognize our voice during training.
We now have a fix in place the returns the full Hey Cortana feature to build 10586 of Windows 10 Mobile. Remember, only phones with a Snapdragon 800 and higher processor can use the feature as it is hardware dependent.
Here is how to fix Hey Cortana if the training does not recognize your voice. The solution takes no more than a few minutes.
Fix Hey Cortana on Lumia 1520 and Lumia 930
Go into Settings > Time & language > Language
Use the + Add Languages function to add English (United Kingdom). Hit the checkmark at the bottom and yes to the download prompt.
On the main Languages page long press on English (United States) and choose Remove. Now, select the Restart phone button and let the phone reboot
4. Add Part II
For these steps, we are reversing what we did above. Use the + Add Languages function to add English (United States). Hit the checkmark at the bottom and yes to the download prompt.
5. Remove Part II
On the main Languages page long press on English (United Kingdom) and choose Remove. Now, select the Restart phone button and let the phone reboot
6. Train Cortana
Once the phone has restarted with the correct English (United States) language you can go back to Settings > Extras > Hey Cortana and begin to train Cortana again to use your voice when the display is off.
*Obviously, if you are a UK users and cannot use Hey Cortana even though you have the feature, you will need to reverse Steps 2 and 3.
Long story short, it appears the language pack with Windows 10 Mobile build 10586 is not recognized as the correct one when using Hey Cortana. All this trick does is reset the language pack and lets the OS recognize it has the right one installed. Hey Cortana and Cortana are dependent on a having the correct region, keyboard and language packs installed. If just one of those are off, it will disrupt Cortana functionality.
We did confirm this worked on our Lumia 1520, so it should work on your phone as well.
Special thanks to NOLATechy, for bringing the solution to our attention