Steve Schear wrote:

As most all on this list are aware, the U.S. Army made frequent and successful use of our indigenous people (often Navaho) for battle field communications during WW II. Now obviously Navaho is a widely recognized language and even our 'oppressive" government wouldn't dare tell such speakers, who might be under investigation for some alledged criminal activity, that were engaging in international communications that they could not use this or a similar form of communciation because LE might not be able to interpret its meaning.

Well, sad to say, a lot of Navajos are being used as intermediaries for "black-ops" projects. It's the sovereignty scam (used when it's useful to them), like British subjects intercepting U.S. phone calls, etc.

What would be the legal status of communicating with a language, too complex for easy human use, which required a computer to structure and translate between other human languages? What would be the ITAR implication of exporting such linguistic software?

You're getting close to something. There's going to have to be a definition of intent for international (and eventually domestic) audio communications, to establish the originator's intent, even ignoring stego issues.

What about speaking or writing riddles or other 'indirect' coding in which the true meaning of spoken or written communication is other than the appearent (literature, especially mysteries have them)? Could export of software designed to create/interpret such riddles or 'hidden' meanings come under ITAR regulation?

If they're not careful, they could open up a juicy can of worms. For example, when the L.A. Times ran a recent headline to the effect that areas around China were becoming a hotbed of weapons dealing and so on, you could interpret that (if you're paying attention) as an invitation to weapons dealers and buyers to "come and get it while it's hot". Look at the time lines for getting secure crypto into the hands of the more-or-less average person, then imagine a much shorter time line for the spinoff programs that do these specialized tasks. Short time lines don't give bureaucrats much time to work with, so if such programs get into wide use, the govt. will have to generalize the prohibitions more than they've announced so far.