My biggest obstacle has so far been language itself: I think I'm too much of an Arabic snob to settle for simple, dictionary translation of some technical terms. I also hate transliterating, so I got distracted by months long process of compiling a dictionary.
To give you an example, Qlb replies with "letter is unexpected" when it really means "symbol". حرف vs رمز. A Lisp evaluator operates on expressions, of which symbols are a subset.
Even within technical English, words like letter and character do NOT mean the same thing, though they are similar.
Most of computational concepts one wants to expound either exist or have strong counterparts in the classical Arabic linguistic, rhetoric and logical traditions. Though not a strict requirement, the Arabic PL designer would benefit greatly from familiarity with the Classical, very abstract and deductive, byt often non-secular, works.
One of my favorite games is to read a passage out, say, a type-theoretic paper and try to translate it to Arabic :-)
[Edit:
It is an excellent hack this, but Arabic side of things could use more polishing. قول is not a verb, but قُل is. قول or مقولة means "utterance", not the very "say" as you might intend. لقوله، قم الليل الا قليلا
]