Setting-up Custom Permalinks for Arabic Wordpress
But in a Blog that's mainly written in non Latin characters (i.e. Arabic), URLs containing posts names would be a real mess: a long series of random & odd letters replace the Arabic characters, & instead of getting Pretty URLs, you get the ugliest you can.
So the easier solution is to use the default WP permalinks, they are said Ugly, but IMO they are not that bad actually, at least they are short.
2nd option is to use whatever customized URLs you want and add a Slug in English letters for each post or page you write & each category (When creating or editing a post, page or category there's a field to enter a custom slug).
The 3rd way, the one I chose, is to not include posts names in custom URLs or categories names, only numbers like dates or posts IDs, I like to add .html or .htm in the end of URLs & add no slashes "/" (a bit like in this Blog), the ".html" thing in the end is to make pages look more regular & not PHP generated; avoiding slashes, is because they look like marking folders, & your pages inside those folders, better that the pages look closer to the domain.
Rest one issue, even if you don't include names in your custom URL, the categories & your static pages will have their names in the URL, so you'll have to change by a Slug written in English (Latin I mean).