How to manage urls of a multilingual website

Hello,

I have a multilingual website with urls looking like that:

https://example.com/en/about/
https://example.com/fr/about/
…/de/about

I need to group the stats of these pages together. But I also want to be able to separate the datas by language if needed.

Do you know a clever way to do that?
I could set a custom url and delete “/en/ /fr/ /de/” but then I lose informations about the language.

Thank you