[martin-adams]

I use the build-in macOS right-click > Speech option. I often use it to proofread things I'm writing and of course to read articles. I've made sure I have the enhanced quality voices in the Accessibility settings.

[shpx]

You can also use this from the command line with

  say hello world

To expand on your last sentence, you need to open System Settings > Accessibility > Spoken Content > click on the System Voice: drop down > click Customize... and then click "Download", otherwise all the voices are still that old school robot voice.

[schwartzworld]

You can pipe to `say` as well