Speak text doesn’t work in Messages app on iOS On most apps on my iPhone (running iOS 13) when I select some text there’s an option to “Speak” the selected text which works fine. However in the Messages app when I long press on a message and choose “Speak” nothing happens. I’ve noticed this issue with two of my friend's phones as well. Any idea how to fix this?
I went into the accessibility settings within the settings in iOS. Under speak selection, I turned the feature off and then turned it back on. And now it works. You might give that a try:

Settings > Accessibility > Spoken Content > ...

Turn off “Speak Selection”, and turn it back on.

That seemed to do the trick.