Hi 4bhv6367,
Thanks for contacting Apple Support Communities!
We understand that you're unable to dictate messages in the Messages app.
Do you have headphones connected to your iPhone or are you using the built-in microphone to dictate text?
Are you able to record a voice memo in the Voice Memo app and listen to the recorded message?
You can also check that the microphone has access to Messages as outlined here: Control access to hardware features on iPhone - Apple Support
- "Go to Settings > Privacy & Security.
- Tap a hardware feature, such as Camera, Bluetooth, Local Network, or Microphone.
The list shows the apps that requested access. You can turn access on or off for any app on the list.
Note: Whenever an app uses the camera (including when the camera and microphone are used together), a green indicator appears. An orange indicator appears at the top of the screen whenever an app uses the microphone without the camera. Also, a message appears at the top of Control Center to inform you when an app has recently used either."
We look forward to your reply.
Cheers!