The point to use a slug (semantic URL) besides of improve the SEO of your articles is to prevent that the user, at the creation of for example an article, it uses special characters that aren't allowed in a URL, appropiate the usage etc. What target usage means, is context dependent.
In this article, you'll learn how to slugify a string in PHP properly, including (or not) support (conversion) for cyrilic and special latin characters.
The following function exposes a simple way to convert text into a valid slug: