[capteasy]

I've "enabled dictation " in keyboard settings. There must be other setting in order for it to work. It only says"tap and hold to record and send audio message" when I tap the mic. It's not working on iPhone 6 or iPad.

[Ledsteplin]

Also enable Siri. Go to Settings >General > Siri.> Toggle on.
If it's on. Try a hard reset:
Hold the top or side power/sleep button and the home button at the same time until the Apple logo appears, then release.
If that doesn't work, try Reset All Settings:
Reset All Settings
Go to Settings >General >Reset >Reset All Settings. This resets to default everything in Settings, including notifications, alerts, brightness, and clock settings like wake up alarms.

If it still does not work, you may need to restore your phone as new. Not from a back up.

[macguy59]

There are 2 different different ways to do audio within Messages (just guessing this is the app you are using). In the new message text box the mic icon is for sending a recorded voice message rather than a typed one. In the keyboard that shows on screen when you tap in the new message text box you should see a keyboard button next to the space bar that also shows a mic on it. This button is for dictating a message that will send as a text message only. It's more confusing than it should be. Think of it this way . . . the mic button in the text box is for sending a recorded message in your own voice. The mic button on the keyboard is for dictating a text message (no audio is sent this way) that will be sent as text only.

[macguy59]

That message is telling you that you need to continue holding down the button until you're done recording your voice message