I want to search for (Library) books about German cuisine specifically Cookies/Biscuits but not for books written in German.
Filtering by Book Types > Baking > Cookies / biscuits and then Browse by Cuisines > German returns seven books but two are in German, which is a language I do not know.
Filtering by Book Types > Baking > Cookies / biscuits and then by Country > Europe > Germany returns the same seven books.
It looks as if language cannot be used as a search criteria (in this specific example as a NOT condition).