When using default values (as provided with #11), it’s only possible to set them for one language. I think it would be best to have them for each language differently.

Agreed, and also localised URL prefixes for slugs.

Localisable default values

Topic		Replies	Views
Localisable URL prefix in Slug fields ✋ Feature Requests slug	11	1940	June 3, 2025
Change localization of backend ✋ Feature Requests launched , localization	1	915	November 25, 2019
Allow arbitrary locale values ✋ Feature Requests localization	0	36	January 29, 2025
Different "Accept only specified values" per locale just like the "default value" does ✋ Feature Requests	4	441	May 29, 2024
Show localised relationship values ✋ Feature Requests	1	652	October 2, 2023