India has an unusually large number of distinct breads for one country. The variety maps closely onto which grain grew locally and what kind of fire was available to cook on.
Wheat and rice divide the map first
The northern plains grow wheat, and wheat contains the gluten-forming proteins that allow dough to be rolled thin and hold together. Nearly every rolled Indian flatbread is a wheat bread.
Rice and other southern grains have no equivalent protein network. Breads made from them cannot be rolled, so the southern repertoire is built on batters that are poured, fermented and spread.
That single difference explains why roti belongs to one half of the country and dosa to the other. The technique follows what the flour can physically do.
The heat source decides the shape
A flat tawa over a domestic fire cooks bread on one side at a time and suits thin unleavened rounds. Roti and paratha are built for exactly that equipment.
A tandoor is a vertical clay oven radiating heat from all sides at once, and dough is slapped onto the wall. That requires a dough soft and sticky enough to adhere, which is why naan is enriched and slack.
Deep oil is a third heat source. Puri and bhatura are cooked by immersion, which inflates them with steam and gives a texture no griddle can produce.
Leavening followed availability
Everyday breads are unleavened because they are made fresh at each meal and there is no time for a rise. Speed is the design requirement in a household cooking three times a day.
Breads that are leavened tend to belong to commercial or occasional cooking, where the wait is acceptable. Naan and bhatura both depend on fermentation or a chemical raise, and both are restaurant staples rather than daily bread.
Fat marks the occasion
Plain roti uses no fat at all. Paratha layers fat into the dough, laminating it so the bread separates into leaves, which costs more and takes longer.
Fried breads consume the most fat of all, which is why they cluster around festivals, travel food and restaurants rather than everyday meals in most households.
The equipment problem in American kitchens
Most Indian breads need only a tawa and a burner, which any US kitchen has. The tandoor is the genuine exception, and no home appliance reproduces its radiant clay heat.
Naan cooked in a domestic oven or a skillet is a reasonable approximation with a different crust. That gap is one reason naan reads as restaurant food to American diners while roti rarely appears on menus at all.