Apparently some time ago Toki Pona was removed as a supported language in Wikimedia. https://www.wikidata.org/wiki/Q11466925 and a bunch of other items still have labels/descriptions/aliases in the language though and can't be edited now via the UI because the validation of the language codes fails.
We need someone to edit all these items via the API to remove them so the items can be edited again by everyone.
T200432#5065475 and the linked ticket describes how this really is an annoying problem.
- none of Wikidata items or properties has a label, a description, nor an alias in language toki pona
- likely can be done by using wbeditentity API and its clear option
- use the user ''Maintenance script' for the API call