I was reading some Spanish grammar stuff, and it mentioned the word "cuyo" as basically meaning "whose". I've literally never heard of this word before, and I've studied Spanish since middle school and even spoken it with people conversationally, so I'm very confused.
It seems like this would be a really common word, but I swear I've never encountered it before. Is it regional, or rarely used, or have I just managed to overlook it for years?
As a native spanish speaker, i rarely use it in normal conversation, but it is pretty common in more academic/formal writing. Where i'm from, if someone's using it it's mostly for emphasis or to make a point by being ironically pedantic. I think most native speakers don't even register when they use it or hear it though. If anything, the only use in which it overrides "que" is when you want to be as unambiguous as possible.
So if you're trying to figure out whom an object belongs to, would you ask ¿Cuyo es este? or ¿De quién es este?
"¿De quién es este?" works better, "¿De quién es esto?" works best because esto is the word you use to mean an object you're directly referring to in general while este is more for when there are multiple objects and you want to refer to an individual one. There might be a better way to explain the grammar behind it but that's the general rule for conversations.
you would ask ¿esto de quién es?, to remember the order remember how you would you respond. "Esto es de él" o "Esto es suyo"
Gracias