Script to target and edit page number

New Here ,

Hi everyone, I'm relatively new to scripting and am currently trying to create a script that will do the following.
Opens a dialog window with a couple of languages the user can select from then depending on the language chosen change the page numbering text frame on the master page. So if the user selects "German" for example "Page A of 1" would change to "Seite A von 1" on the A master page. I've tried using find/change but have had no success yet. Any help would be greatly appriciated