Hello there, How do I internationalize an action's text and desc

What I've seen people doing is creating copies of the applications with names in different languages, it's the same app but different package so the names can be translated and the visibility is managed through the security (e.g. a group for French speaking people, a group for Spanish, etc.)

Is there a way to automatically create a group for a particular Language based on what the user has set as their locale preference?

You can use this function to determine the user selected locale and based on that create a group forum.appian.com/.../Scripting_Functions.html

A user's locale property doesn't seem to be available on the Rules tab to setup automatic population of a group based on this property. I guess we will have to setup a process to administer every user, and put them in the right language group based on locale?

Yes that'd be process based.