That's not an "option" in InDesign, it's how the program is written and the change in shortcuts is automatic when you change OS.
So it is not usable for making a multilingual document
I'm not sure what you are trying to do, or what keyboard shortcuts have to do with a multi-lingual document. can you explain some more?
Sorry for not being very clear.
I'll try to explain it a little better:
My goal is to make a document that contains two languages: English and Spanish.
I was thinking maybe there is an option that you can select text and type the translation of the text.
Then i remembered a video where they showed something (what i thought to be an option).
In the video they were writing a manual for the use of software that was available for mac and windows.
With an option they could change the text in the document were they were describing the shortcuts that could be used for the software.
I've never heard of document that was able to detect the OS and change the text accordingly. Every software manual I've ever used has provided both sets of shortcuts in the text simultaneously.
But that is quite different from a bi-lingual document. We have some experts here in production of documents for multiple languages. As far as I can tell, there is nothing built in in InDesign that would allow you to, for example, click a button and choose a language, though it's not impossible that such a thing could be done via scripting or use of alternate layouts.
I will say, though, that the person whose opinion I respect the most as far as multiple language work is concerned would probably tell you to do two separate documents.
I didn't "detect" the OS, they had to select which type they would print.
But nevermind, i will make two seperate documents.