We heard that Cortana was coming to Android earlier this year and it appears her development is moving along nicely.
Thanks to a tip from one of my followers I was able to checkout her development process on Android.
Things are looking pretty good at this point so check her out for yourself.
What I think is great based on my initial experience with the app - feels a lot like using Cortana on my Windows 10 desktop or Windows Phone.
That is what you call the mobility of the experience.