iWatch microphone doesn't work anymore.

Have you used your Apple Watch in or around water they may have gotten into the microphone (the two little holes on the opposite side of the Digital Crown.) If so, try and dry the watch, or lightly see if you can tap the water out. When your done try using the microphone by using Siri or anything else you've used before.

If that doesn't help then try and power the watch off then back on. If that also fails, then you may want to try to un-pair and re-pair the watch from the Watch app.

If all fails, then it would most likely be a hardware issue that would require a repair. Visit an Apple Store at that point.

Hi

The following steps may help:

Clean your watch, paying attention to the microphone port (the lower of the ports on the opposite side to the buttons), in case it has become blocked.

• Be sure to follow Apple's cleaning instructions, including:

  • Turn your watch off and wipe it clean with a nonabrasive, lint-free cloth. (If necessary, lightly dampen the cloth with fresh water and dry afterwards with another cloth).

  • Do not shake or tap your watch, do not insert anything into the port and do not use compressed air.
  • If the watch has been exposed to water, place it on its side (buttons on top / microphone at the bottom) on a nonabrasive, lint-free cloth to allow any water to drip out. Allow time for any water to fully evaporate (do not use any external heat source).
• Cleaning and wearing Apple Watch - Apple Support
• https://help.apple.com/watch/#/apd707b42a5e
• About Apple Watch water resistance - Apple Support

If you have not yet done so, update your iPhone and Apple Watch to the latest software, starting with your iPhone:

• Update the iOS software on your iPhone, iPad, or iPod touch - Apple Support
• Update the software on your Apple Watch - Apple Support

On your iPhone, go to: Settings > General > Keyboard:

• Check that Enable Dictation is turned on.

On your iPhone, go to: Settings > Siri - disable, pause for a few moments and then re-enable Siri.

Restart both your iPhone and your watch:

• Close all open apps on your iPhone:
  • Double-click the Home button, then swipe up on each app preview to close it.
• Turn both devices off together, then restart your iPhone first:
  • Restart your iPhone, iPad, or iPod touch - Apple Support
  • Restart your Apple Watch - Apple Support

Unpair and re-pair your watch:

• The Watch app on your iPhone takes a backup of your watch automatically when unpairing via the app.
• Choose to Restore from Backup when offered the option during set up. Most data and settings will be restored, with some exceptions (eg Apple Pay cards, passcode).
• Unpair your Apple Watch and iPhone - Apple Support
• Set up your Apple Watch - Apple Support