Flatbreads from India, the Middle East, Central America and East Africa resemble one another closely despite developing independently. The convergence comes from the constraints rather than from contact.
The starting problem is identical everywhere
Whole grain is indigestible and hard to store once cooked. Grinding it into flour and mixing with water produces something that can be cooked immediately and eaten without utensils.
Rolling or patting the dough thin is the fastest way to cook it through, since a thick mass takes far longer and requires an enclosed oven.
Every culture facing that problem with a hot flat surface and no oven arrives at broadly the same answer.
Thinness governs the cooking method
A thin dough cooks through in a minute or two, so it can be made to order rather than baked in batches. That fits a household cooking fresh for each meal.
It also means the bread can be cooked on a griddle, a stone or the wall of an oven, none of which require the sustained heat a loaf would.
Fuel efficiency follows directly, which mattered enormously in households buying or gathering fuel daily.
Puffing is the same physics everywhere
Many flatbreads inflate during cooking, and the mechanism is consistent: the surface sets into a skin, steam forms inside and cannot escape, and the pressure separates the layers.
Achieving it requires a dough with enough structure to hold the skin and a surface hot enough to set it before the steam escapes.
Breads from unrelated traditions puff for exactly this reason, and the techniques for encouraging it are near-identical wherever it happens.
Where the traditions actually diverge
The grain is the main difference, since gluten-forming wheat behaves quite differently from maize, sorghum or millet, and doughs from the latter must be handled without rolling.
Leavening is the second divide, separating breads made and cooked within minutes from those given hours to ferment.
Fat is the third, worked into layers in some traditions and used only on the surface in others, which produces flaky breads on one side and soft ones on the other.
Why the form persists
Flatbread serves as plate, utensil and food at once, which is efficient in a way that no other bread form matches.
It also suits eating with the hands, which remains the practice across many of the cuisines where it developed, and the bread is sized to be torn rather than sliced.
Where those conditions changed and cutlery became standard, flatbreads generally survived as an accompaniment rather than as the structural centre of the meal.