Is there a way to force the iPhone to use its own microphone when connected to a Bluetooth speaker?

I connect my phone to a Bluetooth speaker to play music. When engage Siri or try to use dictation, the phone wants to use the microphone on the Bluetooth device, which is either too crappy or too far away for it to understand what I am saying.

So, I would like a way to restrict the iPhone to using its own microphone even when connected to a Bluetooth speaker.

I am open to doing this via a setting, buying an app, or jailbreaking or whatever.

Is there a way to do this?

The simpler solution would be swiping up on the screen and selecting Airplay to select the output mode as iPhone or iPhone speaker, This will make the iPhone mic in use, but it will remove the speaker from Bluetooth as well for the time being.