[Xtraordinary Gentlemen]

I actually kinda like the idea of an international sign language. I don't feel that the learning curve argument is all that persuasive considering that the aim here is to establish a sign language in nations that don't already have one and thus will have to create or learn one anyway if (when!) this passes. In theory each individual nation isn't doing significantly more work to learn a UN-created sign language than they would if they were to create one on their own. In fact you could probably argue the opposite; the difficulty and cost of implimentation should be lower for the individual nation if the UN creates the language and establishes a training body.