I think "It's not mom, it's auntie" sounds better, doesn't it? Meaning, if there are no articles there. I'm thinking of whether to change the default to this or to "It's not mom, it's the aunt" or "an aunt". Those answers are accepted since forever, but are not displayed as defaults...
But in English we don't typically refer to people as just "aunt" or "auntie" without their name after it. "This is not mom, this is auntie" just sounds strange to my ears, as I would always say "this is Aunt Agatha" or whatever her name is instead. In Ukrainian, is it common to just refer to your aunt as "тітка" without any name after it?
The usage of this/that and це/то somewhat differs between languages. For example, I can easily imagine someone saying: "That's me in the photo!", but in Ukrainian that would rather be "Це я" than "то я". "Those little mannerisms of hers make me sick." - here we also would rather use ці
Right now I checked and I see no hints showing "that". Apart from the discussion about whether it's a valid translation or not, if I add it to be one of the options, I get more than 3000 possible translations because of all the versions of "mom, mommy, mum" etc. that people want to be accepted xD And 3000 is the limit.... So I really don't know whether I should remove one "ma" and add "that" or just decide that це = this and то = that...
This phrase could be used in some situations without it sounding unnatural. For instance, imagine siblings looking at old photos of their parents when they were young. One asks, 'Is this mum?' 'Це мама?' Another looks at the photo and replies, 'No, this is not mum, this is auntie.' 'Ні, це не мама, це тітка.' The implication being that their mother and auntie, her sister, looked alike when they were children; the confusion being corrected using this sentence form.
However, this exercise is to show the form of the sentence 'Ні, це не ..., це ...' 'No, this is not ..., this is ...'
No, if they were talking about themselves they would use "я" (No, I am not ...) and not "це" (No, this is not...)
It can mean "my", "the" or "a". It can mean:
"This is not a mother, this is an aunt", "This is not a mother, this is the aunt", "This is not the mother, this is an aunt", "This is not the mother, this is the aunt". (whatever all of these can mean)
It can mean:
"This is not my mom, this is my aunt", "This is not my mom, this is the aunt", ....
And so on with all kinds of meaning combinations.