Mic not working for talk to text or Siri

I have an iPhone 6Plus. About a week or two ago the mic stopped working for talk to text. I don't use Siri often, but checked that out to see if I could talk to Siri and I can't. I've checked all settings and Siri is turned on and in the correct language. Dictation is enabled for keyboard. When i try to use talk to text I touch the mic icon at the bottom of the keyboard. The grey dictation window comes up and and speech recognition line appears, however the little mic icon at the bottom of the screen has a line thru it as though it is muted and the phone does not pick up any sounds at all. Any ideas??