If you're using Cortana on Android, you might want to head to the Google Play Store now and check for a useful update. Indeed, Microsoft has just updated the assistant to version 184.108.40.2065, now allowing users to use it to call or text contacts without tapping on the screen (via Android Police).
Though not exactly earth-shattering, you can try out the calling feature by summoning Cortana and saying "Call [contact name here.]" Similarly, you can use Cortana to text a contact by saying "Text [contact name here] [message here]." See it in action below.
The feature is a bit time-saving at best, and we're hoping Microsoft can add even more functionalities to Cortana on Android soon. For now, though, you can check out Cortana by downloading it via the link below. Once you've downloaded or updated, feel free to let us know your thoughts on how Cortana is working by dropping us a line in the comments section.