Yes, it makes sense if you had a document that was mostly in e.g. en-GB, with some phrases in fr, ang and la and you had dictionaries for British English and French but not for Latin or Anglo-Saxon, that it would pass by those Latin and Anglo-Saxon phrases.
I think the ideal would be a list of languages in the document that weren't checked for that reason.
Yes, it makes sense if you had a document that was mostly in e.g. en-GB, with some phrases in fr, ang and la and you had dictionaries for British English and French but not for Latin or Anglo-Saxon, that it would pass by those Latin and Anglo-Saxon phrases.
I think the ideal would be a list of languages in the document that weren't checked for that reason.