The APL family languages (and their users) have always fascinated me somewhat because they seemingly go against the common wisdom of what it means for a programming language or code written in it to be "readable" --- i.e. instead of the widespread notion that good code should be like English, it turns that concept around completely, treating a programming language like an actual language. APL is as foreign and unreadable to a typical Westerner as Chinese, but just like with natural langauges, you realise that there are many who have learned and are proficient at using them.

In other words, with many programming languages it's "the code is unreadable because it's not sufficiently English-like"; with APL, it's "the code is unreadable because you don't know the language."