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IDN Language Tags (NeuStar)
When registering IDN domains with NeuStar you have to specifiy a special language tag, which states what language/character set the domain name is in. The language tag is not the same as the ISO Country code. Please take a look at the accompanying table for a list of valid IDN language tags. Complete lists with valid characters and reserved domain names can be found on the NeuStar website http://www.neustarregistry.biz/node/52.