This discussion is funny.
Sandwich is an English word we also use in my language. Not to refer to any sandwich (we have own our word for that) but specifically for the ones made with sliced bread (which was not typically made here).
Therefore for me a
sandwich is only something made by two pieces of sliced bread and fillings, and it's hard to think that something else - a burrito, a hot dog, whatever - is a sandwich.
Then again I could try to use my language's word
bocadillo, which should - by definition - include all sandwiches.
(The actual definition is: Piece of bread cut in two inside of which you put or spread some food.)
But no, I can't think of those things as a bocadillo either. For dog's sake, I can't even think of a sandwich as a bocadillo!
For me the word refers to the traditional bread ones, not sliced bread (which most times is hardly a proper bread) nor tortillas nor buns.