Hi
I don’t think that will work.
Standard language in windows setting can be as you prefer
But the settings for "Language for non-Unicode programs" system locale has to be changed to "Latin (World)". (not English or any other codepage)
And if checked, uncheck "Beta: Use Unicode UFT-8 for worldwide ..."
At least at the two PC I have tested on (both is danish versions of windows 10) - it has worked 
Note: It didn't help here (RStudio can't deal with file names with unicode characters - #16 by mirirai).
... but I would still suggest you first try changing to Latin (World) for "non-unicode programs"
Brgds. Henrik