urls – Can non-latin characters appear in slugs?

For a non-latin category name such as “我的种类”, the slug generated is “%e6%88%91%e7%9a%84%e7%a7%8d%e7%b1%bb”. What function does WordPress use to generate this slug? Can I directly use “我的种类” as the slug? I tried to change the slug from “%e6%88%91%e7%9a%84%e7%a7%8d%e7%b1%bb” to “我的种类” in wordpress database, but when I visited http://example.com/category/我的种类/, it showed “Page not found”. If I did not do the change, I could visit the category page without a problem by typing http://example.com/category/%e6%88%91%e7%9a%84%e7%a7%8d%e7%b1%bb/ or http://example.com/category/我的种类/ in the address bar of my browser. In fact, if I type http://example.com/category/%e6%88%91%e7%9a%84%e7%a7%8d%e7%b1%bb/, it is automatically changed to http://example.com/category/我的种类/ in the address bar,why? And, are non-latin characters not allowed in a url?