How is the easiest way for one to duplicate his git repo for a new same purpose or creation but will be coded using another programming language ?

Do you need a different repo if you want to add a new language? Probably, no. It may be best to keep it all in the same repo.

Very interesting !

have been thinking the other way around, is it just me?

If you release a particular version, do you do it per language or does the release include all supported languages?