How to get spoken instructions from Google Maps while bicycling?
One of these solutions may help, assuming muting Volume is not the cause


Download Voice Directions by keeping map open and getting directions



  Sometimes voice directions aren’t downloaded or need to be updated on your phone or tablet. When this happens, you’ll hear a chime instead of voice directions.



Solution for same problem from Maps help


Uninstall and reinstall Maps updates
Ditto for play services
Clear Cache of maps before navigation