Username mixed Languages

I Can enter a username in any language, but if i mix englisha nd another language it tells me Invalid Username. Can this be changed somewhere?

I was able to create a username with cyrillic (russian) and latin (english) characters mixed - тестabc. Can you post what username you are trying to create exactly?

Joel יואל

this is hebrew and english

The above name also contains also an RTL (right-to-left) character. This makes up an interesting JID. contains information about it. It could simply be prohibited to create such a name.

So is there anyway to allow it?