A taco is, of course, a folded tortilla that has been either fried or softened in the oven or on the stovetop; a rolled taco is, by definition, rolled and not folded. The difference between a taquito, literally "small taco" in Spanish, and a taco is straightforward -- both the size and the shape are different. But the differences between a rolled taco and a taquito are not so distinct.
A Mexican restaurant in San Diego, California, El Indio, claims ownership of the word taquito, and it may well be true since many other restaurants forgo the word taquito and use the more common term flauta, meaning "flute," instead. In fact, a flauta, a taquito and many rolled tacos are the same food, a tortilla rolled around a savory filling and fried until crispy.
While all taquitos are fried, rolled tacos are either fried or baked. To fry a taquito, place filled tortillas in a pan of oil heated to 350 degrees Fahrenheit and cook them until they are golden brown on all sides, about 4 minutes total. Or, for the same crispy texture, bake the taquitos or rolled tacos in the oven at 425 F for 30 to 35 minutes, or until they too are golden brown.
While rolled tacos and taquitos can have all sorts of fillings, regional variations exist, both in Mexican cuisine and in American Mexican cooking. According to chef Rick Bayliss in his book, "Authentic Mexican," rolled tacos, called flautas in most of Mexico, are frequently filled with beef and not pork. He notes too that in the Yucatan, the tortillas are filled with a spicy beef mixture called "picadillo" that also contains raisins, almonds, cinnamon, cloves and cider vinegar.
The transformation of flautas into rolled tacos and taquitos is a natural blending of foods and culture. Think of Tex-Mex rolled tacos and taquitos as simply a regional variation of Mexican flautas blending with Texas, Southwest and Anglo additions. The Spanish influence comes through in the word "taco," and Native Americans contributed corn, now used to make corn tortillas. Like the differences between a rolled taco and a taquito, tracing the origins of foods is a complex process.