Microsoft"s "Hey Cortana" feature brings voice activated commands to your PC and mobile devices running Windows 10, and today, Microsoft has brought an important feature to select devices running Windows 10 Mobile which helps "Hey Cortana" better recognize user input.
An update for Lumia 930 and 1520 devices running Windows 10 Mobile recently went live, and includes a new training mode for the "Hey Cortana" feature. Going through the training process on your supported device helps Cortana respond to you better when you say the "Hey Cortana" phrase. As you progress through training mode you will be prompted to say "Hey Cortana" five times - each time helping the software better learn your speech patterns so the feature is more likely activate successfully on each attempt.
The new speech trainer is currently found under the Settings menu within Windows 10 Mobile on Lumia 930/1520 devices that run Windows 10 Mobile, instead of Cortana"s Notebook section these kinds of settings typically fall under. It"s likely that Microsoft will bring this training mode to all Windows 10 Mobile devices in time, but for now the feature is limited to the Lumia 930 and 1520 handsets.
Source: Windows Central