I don't think you can use macros for the URL path or pattern. If you scroll down to "Using language prefixes for URLs" in the link that David provided, it describes how to ensure there is a prefix.
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 <domain>/<language prefix>/<URL path>, for example: <domain>/fr-FR/Home
To enable language prefixes, go to Settings -> URLs and SEO, and enable the Use language prefix for URLs setting.
Note: You cannot use language prefixes if the Force domain culture setting is enabled.
You can also change the prefix text:
Changing the language prefix text:
By default, the language prefix matches the culture code of the requested language. If a culture alias is set for the language, it takes precedence and the system uses the alias instead of the culture code. If you want to change the language prefix for a certain language, the best way is to set a culture alias.
For example, to change the language prefix for the French language to France:
Open the Localization application.
Select the Cultures tab.
Type fr-fr into the Culture code filter and click Search.
Edit the French - France culture.
Set the Culture alias property to France.
The system now displays the language prefix in URLs of French page as for example: