Non-ASCII characters can be used in the URL, but they have to be encoded (RFC3986). URL encoding is widely used (e.g. Wikipedia http://ja.wikipedia.org/wiki/Wikipedia:%E9%80%A3%E7%B5%A1%E5%85%88).
This plugin encodes NON-ASCII characters in the slugs of your pretty permalinks. So your slugs may look like fußball-in-nürnberg or 連絡先.
安装:
Upload this plugin to the /wp-content/plugins/ directory
Activate the plugin through the 'Plugins' menu in WordPress