> I've always found it intriguing that a programmer who could
> master several arcane computer languages (especially since
> computers are notably intolerant of errors), could fail so utterly
> to master his own native human language.
I believe it is precisely the fact that spoken or written languages ARE tolerant of errors that prevents people from mastering them. I'm reminded of an email that's floated around for a long time referring to some university study where a paragraph of text was still legible even though every single word was egregiously mispelled. It was close, and therefore "close enough" to effectively communicate a message.
You can see this same thing when comparing programming languages -- many of the more strict ones force you to write clearer and better code, while more lax languages allow you to write really bad code and get away it. (Of course, there are always exceptions to that)