Changing allowed characters to disallowed characters without risking anything?

[eluser]Mohsen32[/eluser]
I need non-English letters in my URLs, and basically CI doesn't allow that, so how one can change allowed characters to disallowed characters without risking anything?

[eluser]Aken[/eluser]
You can encode all of them to their HTML entities which would eliminate any issues, but the URLs will be kinda ugly.

[eluser]Mohsen32[/eluser]
Hi Aken,
Can you provide me with some more info about these stuff, HTML entities. After all, I am newbie here.