Does it say हमारी because it's a female friend?
Yes. दोस्त can be male, female, or plural. The only way to tell is from the articles (हमारी, हमारा, हमारे).
Why can't we say "Neha humari dost hai kya?"
Wait, I thought क्या was "what"
In this sentence and others like it, it turns it from a statement ("Neha is our friend") to a question ("Is Neha our friend?").
क्या is merely a "question marker". Its meaning changes depending on where it's located and what it's in relation to.
Not a pro on this, but I have noticed that when क्या is the first word in a sentence (question) it usually translates to "Is" or "Are". When it is the second it seems to mean "What". Weird I know...
Yep at the beginning of the sentence it turns the sentence into a question. When it is within the sentence it means what.
Why cant we say नेहा हमारी दोस्त है क्या?
It's correct and can be used.
Isnt "dhosth" a masculine gender?
It depends if it is a male or female friend. (See the reply on the first answer.)
If we leave out क्या, does it make the sentence ungrammatical?
It is possible. It depends on how you inflect your voice. You would say something like, "Neha is our friend?" With an inquisitive tone.
This would mean "Neha is our friend"
Is typical English punctuation not used in Hindi (such as question marks, commas, etc.)? Just curious since I'm learning to write it as well
The punctuations are used in Hindi as well. They actually remain the same, but full stop sign changes to 'poorn viraam' indicated with a straight vertical line "|".
Is हैं must for all the sentences?
Is क्या नेहा हमारी दोस्त not correct