Recognision of one ICAO document or one IATA document?

I have the young friend of 22, who asked me the assistance for him. His is a native Arabic passenger.

The ICAO is independent international establishment or it is under UN?
What international body the IATA is under?
There are 6 official languages, which are recognozed by UN: AR, EN, CH, ES, RU, FR.
So the passenger can ask the tickets to be translated for the passenger from air carrier accordng to local rules.
But the other international document excludes 2 languages from the above and recognizes 4 only.
Where and why 2 languages have beed llost?
Thank you for the sharing of ideas, the civil aviation professionals!

This problem persists in Europe also, in Finland no doubt.
Finland has a chance to check the validity of e-mails and of the adresses of passenger in their administrative recognized body and in the supervising body.
Calculations for impropper execution (percents) of the duty come from June 25, 2013 - reported.

The second question is for legal professionals and civil aviation professionals only.

ICAO is an internationally recognised body for the regulation of civil aviation from 1944, which has their own constitution.
It had been govering the air transporatation servises of an air carrier and a passenger from 1944.
The term “travel” relates to any travel, beyond by air (term “beyoun legal doubt” or “beyoung reasonable need”).
What the representative of travel agencies do in ICAO ? I do not see one graound ever granating the legal excuse to be a part of ICAO for representatives of “travel agences”, afterf i have put my eyes to the their constitution and to their main documents - very first conventions, 1944.
Thank you for the sharing of ideas, legal and civil aviation professionals!