If your Mac doesn’t recognise text and commands you speak
If your Mac is having trouble recognising your dictated text or spoken commands, you may be speaking too loudly or quietly into the microphone, or there may be too much background noise. Here are some solutions to try:
If your Mac doesn’t have an internal microphone, make sure an external microphone is connected to your Mac and selected for use in system preferences.
Be sure the microphone is not obstructed by objects, such as clothing or your body, while you’re speaking. Check the user guide that came with your Mac to locate the built-in microphone. See Find the manual for your Mac.
Be sure the input volume of an external microphone is sufficient. If you’re using an external microphone and you don’t see the meter respond to your voice, select the microphone in the Input pane of Sound preferences and adjust its input volume higher (choose Apple menu > System Preferences, click Sound, then click Input).
Position yourself as you would normally use your Mac, then speak in a calm voice that’s not too quiet or too loud. As you speak, the feedback window gauges your speaking volume.
Avoid background noise. If you use dictation in a noisy environment or a room with excessive echo, it may help to use a headset microphone.