Siri doesn't work unless using an external microphone.

Hey there chattphotos,

It sounds like you are unable to use Siri unless you have a headset with microphone in it.

I would start by quitting all the running apps on your phone:

iOS: Force an app to close

http://support.apple.com/kb/ht5137

Double-click the Home button.

Swipe left or right until you have located the app you wish to close.

Swipe the app up to close it.

When you have done that restart the phone and test the issue again:

iOS: Turning off and on (restarting) and resetting

http://support.apple.com/kb/ht1430

Thank you for using Apple Support Communities.

All the very best,

Sterling

Next I would back up the phone to iTunes:

iOS: How to back up and restore your content

http://support.apple.com/kb/HT1766

Then Restore your phone to factory settings with the following article and set it up as a new device first, and test Siri.

Use iTunes to restore your iOS device to factory settings

http://support.apple.com/kb/ht1414

If It works fine, then restore from your backup and verify that it still works to help isolate an issue with the backup data.

If it does not work, then your phone will need service:

iPhone Repair - Other Repairs

https://www.apple.com/support/iphone/repair/other/

Thank you for using Apple Support Communities.

All the very best,

Sterling

I am having the same issue here, all of the steps you have given does not work to solve the problem. This is obviously a software issue, how can it be fixed?