For what it's worth, there are at least two localised versions of Python: Teuton and ChinesePython. As far as I know, ChinesePython is still in active development. Both translate the keywords and builtins, to German and Chinese respectively. I don't have a link, but I recall that Guido gave his blessing for ChinesePython to call itself a Python implementation.

There's a localised, Portuguese version of Stack Overflow:

http://blog.stackoverflow.com/2014/02/cant-we-all-be-reasonable-and-speak-english/

so I think that the days when all programmers must learn English are slowly fading away, just like the days when all mathematicians had to learn German.

But, I agree with those who say that a PEP is necessary. There are a lot of factors to consider. (Although of course as a third-party library, no PEP would be needed.)