Android TTS to speak Meshtastic messages aloud is possible with an app, called Voice Notify. It uses the Google TTS voice engine with access to the many voices and language options Google provides. Though it’s limited to selecting one voice, it works well to read messages aloud.
The app works by reading your notifications. It can easily be configured to read any part of notification contents.
In Android settings, using App Notifications to customize the notification sound of the Meshtastic app while setting Voice Notify to a two second delay before speaking works to emulate a radio-like experience.