Asian language subdomain name

I suppose this question could be for WP Support forum, but here goes…

I have a multisite subdomain network. I’m trying to create a subsite with subdomains in Thai. I’m going to register an internationalized domain name (thai language) and add it to multi-site and add sites under that domain… the thai domain can be added to Multi-Domain with no problem, but Add Site is not recognizing the thai for the subdomain name – showing error “Missing or invalid site address.”

I tried using the multilanguage plugin and setting primary site language as thai but no effect on error, still says missing. I know you can install WP in Thai, but that would be difficult to manage (that is an understatement) and not sure it would recognize Thai for the subdomain.

Any ideas? seems like this would be an issue more and more people will see as internationalized domains become more common. thanks