As stated in this KnowledgeBase article: http://help.filemaker.com/app/answers/detail/a_id/8079/kw/Get%28ApplicationVersion%29
You can use Get ( ApplicationVersion ) to tell the difference. A script can be set to run when the file opens that uses this test to specify a layout appropriate for the current device.
I've asked in another thread whether or not ALL languages return "iPad". If not then that answer is insufficient. If not the same in all languages then using the screen width dimension might be a better choice.
If system platform is 3 and screenwidth is less than 768 (whatever) then it is an iPhone otherwise an iPad. No language problem.