As a native English speaker who's tried to learn Japanese, the distinction between Perl, APL, and their ilk and other languages to me seems more akin to ideography vs. syllabary/alphabet (i.e., characteristics of the writing systems) than to natural language vs. computer language.
My big problem with reading and writing Perl is the same as my problem reading and writing Japanese: there's just so much you have to flat-out memorize. Look at the index to the Perl book: it begins with a vast collection of arbitrary symbol pairs. Sort of like written Japanese words are collections of often somewhat arbitrary ideographs, because many words were borrowed from Chinese over many centuries, while the Chinese writing system was evolving.
Of course, people still learn to read and write Japanese fluently; it just takes a long time (12 years of schooling). I bet I'd be fluent in Perl if I spent 12 years learning it as well. But I'd rather not have to do that to use a programming language well.
This is off-topic, but I don't think it's fair to say that it takes 12 years to read and write Japanese fluently. That's just the time that it takes to graduate from high-school in Japan.
In fact, the mandatory education in Japan comprises only elementary and junior high school, which takes 9 years in total. By the time you graduate you're supposed to know all of the 2000ish 常用漢字 (Jouyou Kanji=Common Use Kanji). If you add a couple of hundred of place and people names, you'd get a good approximation of "fluent reading and writing Japanese", as far as kanji is concerned.
If you're learning on your own, there's no reason it should take 9 years. If you learn it at a rate of 10 characters a week, you could learn 2000 in 4 years.
That said, I think the emphasis people put on learning a lot of kanji, without being able to speak the language, is misguided.
Except that it's not, because there are many good alternatives to Perl that have equivalent, if not greater, power, and require very little memorization. You can be up and running with a full understanding of the syntax for most flavors of Lisp in a few hours...
Actually, Feynman had exactly this criticism of the way biology was taught; that the students memorized way too many things that they could just look up(and this was pre-Google, mind you!)
My big problem with reading and writing Perl is the same as my problem reading and writing Japanese: there's just so much you have to flat-out memorize. Look at the index to the Perl book: it begins with a vast collection of arbitrary symbol pairs. Sort of like written Japanese words are collections of often somewhat arbitrary ideographs, because many words were borrowed from Chinese over many centuries, while the Chinese writing system was evolving.
Of course, people still learn to read and write Japanese fluently; it just takes a long time (12 years of schooling). I bet I'd be fluent in Perl if I spent 12 years learning it as well. But I'd rather not have to do that to use a programming language well.