>> Na'vi reminds me of Dnghu in a way. No attempt to be less difficult
>> than a natural language (though I think it's almost impossible to
>> create a language more difficult than a natural language unless you're
>> really trying to do so) and without a complete grammar or dictionary,
>> and yet there's more interest out there for it than languages that do
>> their best to be easy and accessible.
> Problem is, I guess, that it is harder to meet real need than imagined one.
> Like this. How many speakers of Klingon do you think there are who don't
> speak English?
> I guess none!

That's right. The reason for that: Klingon first began to be learned
back when people were using VCRs to watch movies. Fast forward to 2009
and even if you're a monolingual Bulgarian you can watch 295 videos
from in your native language:

Now that it's 2009, the only thing a monolingual person needs to learn
the basics of the language is a translation of the English Wikipedia
page. The grammar for the language hasn't been published (apparently
because the rights belong to the producer, not the creator of the
language) but there's still quite a bit that can be learned from
existing samples alone.

Star Trek is also completely different from Avatar - in the 24th
century everyone uses a universal translator to communicate. Avatar is
more realistic linguistically, where most people can't communicate but
a few of those high up among the Na'vi speak English while a few
scientists among the humans can speak Na'vi.