I'm thinking of creating a website in my mother tongue, but of course I cannot even dream of getting organic traffic because we all search in English, not that its a crime, but suppose I do, how popular could it be and if it's going to be interactive, how popular would it be ?

Right there, you are limiting yourself. What is wrong with you coming up with a search engine written in your language? Must you always be a consumer?

Regardless, I have a website that serves as a dictionary for my language. It gets hundreds of hits a day. Sure, it is written in English but the bulk of the content is in my language. So, don't worry about the base language. Build it and if people see value in it, they will come.

Good luck!