One thing that never came up during the cataloging courses I took, but should have, was that the fields in MARC records may mean certain things to the cataloger who's entering and editing them, but that doesn't mean they're understood and put to use in the same way by the OPAC. I got a reminder of that today.
I had assumed that the language dropdown menu in our advanced search limited searches to the actual language of the items (in my cataloger's brain, I thought it limited searches to whatever language was listed in field 008 positions 35-37). That would still make multi-lingual materials problematic, but it's better than nothing, right? However, I didn't realize that the dropdown was just drawing from all languages associated with the items. That means that, if you selected German as the language, you'd not only get materials in German, you'd get materials in other languages that are translations of things originally in German. Not exactly ideal if what you want to find is a book in whatever language you're interested in. Not everybody wants translations.
Ideally, there should be a way to limit a search by the language of the actual item and, separately, by the language of the original work. (Which is a simplification, because MARC records also include things like "language of subtitles," "language of librettos", etc.) Instead, I think we've just got an either/or situation with our ILS. Right now, "language" in our advanced search is defined in a very broad way, and, if we narrowed that definition (if that's even possible) by changing our settings, we'd lose the ability to find, say, a book that was originally in German by choosing German from the dropdown.
I figured out a way around "too broad" problem by using a report in WorkFlows ("List entries from catalog", searching for the correct language code in 008, and limiting by call number, library, etc. if desired), but this workaround is clunky. Also as far as I know, there is no way for the average user (or staff members or librarians without WorkFlows access and knowledge of MARC) to find only materials in specific languages. I'll have to think it over and see if I can come up with anything. It'd be interesting to see what others assume the language dropdown is supposed to do - it's possible that our settings could use some tweaking, even if that means losing the ability to find "translations of works originally in X language."