Whisk together the flours, salt, sugar and baking soda in a mixing bowl. Add the yogurt and mix with a spoon until a shaggy dough forms. Turn out onto a floured board and knead briefly until it comes together. Divide into 6 pieces.
Warm a skillet, such as cast iron, or a griddle over medium heat.
Flatten a piece of dough slightly, and using a rolling pin roll it out into a rough circular shape about 6-7 inches. Cook one at a time in your skillet for about a minute a side, until browned evenly. Remove to a plate or wrap in a dishtowel. Repeat with the remaining dough.
Breads are best when eaten soon after cooking, but can be made ahead of time and rewarmed in a low oven.