1. Select a voice and click on the cloud symbol to download it.
We are using a French voice in this example.
2. Click OK.
IMPORTANT: Always choose the Premium (the best) or Enhanced quality of a named voice, if offered a choice. These give much better quality audio than the standard voices.
Note: on older versions of MacOS, scroll down to the language you want, tick the named voices you want and press "Play".
Then click OK to confirm your choices, and the voices are now set up.