Math have localized names for Greek characters. I don't know which is
the situation for other languages but the Spanish translations are
simply horrible: for example, instead of épsilon (right spelling)
you have epsilón (very wrong spelling: notice the different accent).
There is a related issue
I think that one (between many) errors when some translation is made, is
the dubious use of the spoken language and the written form of the same,
some many times seems to be more familiar but.. quite erroneous.
You are entirely wright to point that the correct speling in Spanish is
épsilon and
