It's not as easy as just translating "dì" to "aunt". It depends on the context. If you are talking to your aunt it would translate as "you have an umbrella." Also dì is used when addressing you mom's sister. There are other names for aunts depending on how you are related (cô, thím, mợ, etc..). Someone please correct me if I'm wrong.
I'm thinking where this is coming from is that Auntie would probably be used as a pronoun, but Aunt isn't really used any more. Maybe as a term of kinship, but not really with the capital letter. Auntie has an umbrella sounds fine, but maybe to people who use aunt it'd sound fine.
Its confusing but im starting to understand a bit. If u broke this down. It would be out of context and would make no sense. Cai is added before o so the prrson listening can determine what it is your speaking of. Like categorizing since many words have similar sounds which can be easily misinterpreted without that 'cai' classifier.