Lang. in rfc1766

In rfc 1766 it uses example languages like en-cockney, az-arabic and
az-cyrillic.  But these examples don't seem to be registered with the
IANA.  As far as I can tell, the IANA has only registered 4 languages:

no-bok    Norwegian "Book language"
no-nyn    Norwegian "New Norwegian"
i-navajo  Navajo			
i-mingo   Mingo

Are teh examples given above actually useable?  If so, where are they
registered?

-- 
Russell O'Connor                           roconnor@uwaterloo.ca
    <URL:http://www.undergrad.math.uwaterloo.ca/%7Eroconnor/>
"And truth irreversibly destroys the meaning of its own message"
-- Anindita Dutta, "The Paradox of Truth, the Truth of Entropy"