Title. I went into the in-game options, but I'm only getting an option to change in-game text, not audio.

Found a number of threads online claiming that if you went into the Properties section on Steam and changed the language, then the audio option would appear, but I tried that and no luck, even after uninstalling and reinstalling. Notably, at least one of those guides was a video showing an old UI where the Properties window had a Language section--the current UI just has a single Language dropdown menu under General.

I also already tried editing the user.settings file to say ES instead of EN for both language lines. No effect at all.

UPDATE from midway through writing the post: I tried setting the Steam Properties to a few other languages, and for some of them, as soon as I set it, it started installing a new multi-gigabyte "update" (5GB for French, 3.6GB for Korean, iirc). Not so for Spanish or Italian. So I guess the question has changed to, how do I get Steam to download the update for Spanish?