Have messages read out loud in Messages on Mac
Messages can speak the text in a transcript, the Messages window, or a profile window.
Siri: Say something like:
“Read my messages”
“What was my last text?”
In the Messages app on your Mac, select a conversation or select text to be read.
Choose Edit > Speech > Start Speaking.
To make the speaking stop, choose Edit > Speech > Stop Speaking.
To change the computer’s speaking voice, choose Apple menu > System Preferences, click Accessibility , then click Spoken Content. Click the Help button for more information.