Hey @TomAPREA 
Thanks for the post! I know you’re looking for input from some of our users on this, and am hoping some others jump in, but wanted to provide some quick resources in case they’re helpful. First, here’s the section from our manual on using the built in languages feature. I’d highly recommend giving that a look.
One thing I’ve seen some users do is trigger a popup to show when the current user (logged in or not) doesn’t have a language set. This could show them the flags of various languages and allow them to choose. The index could then be set to respond and change the language based on what’s selected. Worth looking into at least!
Give it a try and don’t hesitate to reach out with any additional questions to [email protected]