Many books don't include the language but Readarr leans on this heavily with their Metadata Profile for filtering out irrelevant books. We should look into language detection for books. Some ideas:
Language prediction based on title/description
Series names for translations often include the language in the title (i.e. Harrius Potter (Harry Potter, Latin))
The translated_from and translation_of indicate the original book was translated
Many books don't include the language but Readarr leans on this heavily with their Metadata Profile for filtering out irrelevant books. We should look into language detection for books. Some ideas:
translated_from
andtranslation_of
indicate the original book was translated