Between yesterday and today, the little microphone icon no longer appears just above the keyboard to allow me to dictate to the phone. I used this quite a lot to dictate SMS and What's app messages. As far as I am aware, no updates have happened on the phone. I am running Windows build 10.0.10586.164 on Lumina 640 XL LTE. I can still use voice recognition for Cortana, but not the keyboard.
What might I have done, how can I get this feature back?