WP Tags in a Mess!

I’ve recently change all of my tag name bilingually, but I remain a English slug. So, whenever I am adding a new post, and select the tag name I wish to add, WordPress System automatically create a new tag with the same tag name but a slug is in two languages same as the name, which is not browser-friendly any more.
Does the slug is necessarily as same as the tag name?
who can help me?
Thanks!