Any thoughts about what this is supposed to do and what it actually does? - All I seem to get whenever I try this is a mixture of underscore, dash and gobbledegook.

Maybe you can expand...  Is this a product or a setting?  Is it for 2020 or 2024?  I googled but no response so I guess my first thought would be what exactly are you talking about? 🙂 

3 minutes ago, cianpars said:

Any thoughts about what this is supposed to do and what it actually does? - All I seem to get whenever I try this is a mixture of underscore, dash and gobbledegook.

Not so clear on what “this” is and what it is exactly that you are trying to do 

It's a settig in the language tab of general setings in msfs2024.   Surprised that nobody seems to have come across it or knows what it is actually supposed to do.

12 hours ago, cianpars said:

Any thoughts about what this is supposed to do and what it actually does?

The explanation you get when hovering your mouse over the option seems clear enough, no?

1 hour ago, Rimshot said:

The explanation you get when hovering your mouse over the option seems clear enough, no?

The explanation is clear but it results in gobbledegook.

Here's what Search Assist says:

Authentic ATC Language in Microsoft Flight Simulator (MSFS) refers to a feature that aims to provide realistic air traffic control communications using standard phraseology. However, users have reported issues with mispronunciations and mixed language outputs, especially when the text and spoken language settings differ.

"msfs Authentic ATC Language" gives a planeload of results to look thru.

The Authentic ATC Language feature is cool, but as mentioned results in a mixture of underscore, dash and gobbledegook.

Unfortunatly to get rid of all that you have to change the setting to the other setting and it gets rid of all the gobbledegook but also the accents.