[rossjudson]

The notation can yield very dense programs. Significant systems have been written that can be expressed on a screen or two of code (search Arthur Whitney APL for "the legends").

When we learn to read, we learn to "sight read" words. APL/J/K constructs can be "sight read" as well.

[pmoriarty]

Sight-reading is a great analogy because as with music, in order to stay fluent and make one's performance (or sight-reading) easy, one has to stay in constant practice.

I'd argue that much less of this is required for languages like Lisp, unless, of course, you step away from practicing reading English, in which case maybe the very English-like programs of Lisp will start to seem foreign to you.