I believe you can use the Kentico Culture prefix functionality:
https://docs.kentico.com/display/K9/Configuring+URLs+for+multilingual+websites
Using language prefixes for URLs
If you do not own a different domain name for each language version of the website, but still want to ensure unique URLs for each culture without adding query string parameters, you can use language prefixes. Language prefixes insert a subdirectory into the URL in format