Greek language question: I always called my aunties something that sounded like “Thea-“ and then their name. I thought that meant auntie, but you call yourself “theitsa” and from what I understand that also means “auntie.” Why do I call my aunts something different? Our family comes from Kalamata, if it’s a regional thing
Tbh I don't know if it's original thing in your case but in standard Greek the word for aunt is "theia" (θεία), and for auntie it's theitsa ("θείτσα"). So, you simply call them "aunt". But in Greek using "theia" is pretty standard and I (personal experience) haven't heard anyone call their aunt "theitsa" unless they want to beg for something and be extra sweet. Theia is pretty sweet on it's own.
Theios and theia are also used for older people who are like family or if you want to be polite to some older person on the street. (It depends on the situation again but I've used it once or twice). If you are using it for people other than the siblings of your father and mother, you'll know when to use it. It's not used much these days but there are some elderly who like it if you call them this.
Sometimes, the diminutive form can be a bit negative in the sense that sometimes it's used to describe a "generic" type of theia, or a theia who cannot be taken seriously, who has a small importance in your life. E.g. "There's a theitsa in the village that always asks me where I am from". I'm not sure if I explain it very well but you can ask your theies if they want to be called that xD Maybe there's another, similar word for "aunty" from Kalamata that they'd prefer.
To sum up, theia is very fine and cute on it's own and most Greeks use that most often. Theitsa is extra cute or extra familiar so it's used sparingly.
Anyone who wants to add something feel free to!