I think you should ask this in the other way.
Does not knowing English make it very difficult to
program (in perl or anyway)?
My answer is yes.
You must definitely know English at least to some very
basic level. However, this basic level is not very
difficult to aqquire, beacuse you have to understand
only technical words, and the documents itself
are often written by people who don't speak English well.
To program, you have to be able to read the manuals.
While some books of perl (and even some of the core
perldocs) are available in translation, it's still very few
as compared to those in English.
It would be impossible to translate everything to every
language.