I'm putting together a custom search page using the PNP search web parts. I have my search results working fine, but it's for a tenant that's using the SPO multilingual pages and I want to refine by the language of the page.
There is a property SPTranslatedLanguage, which shows the language of any page that's a translation, but shows null for a page in the default language. So if I have the default language on the site as English with French and German as an available translation languages, then the translated pages will be tagged as French or German in this property, but the original English page that they're translations of will be tagged null.
This means if I map SPTranslatedLanguage to a refinable string property and add this in the search filters web part, I can refine by French or German, but there will never be an English option to refine by. Does anyone know how I could create a refinable property that would let me filter by the default language as well?