There is a roti shop in Upham's Corner so I could easily answer the question myself by walking through the front door, but that would detract from the air of mystery about this food. My first thought is that it is some kind of croquet, a ball of dough wrapped around a ball of other ingredients and then deep fried. I don't have any reason to think this. I just do.
I've seen roti shops in Mattapan and other neighborhoods but I was never hungry when passing through so my ingnorance remains unsullied by experience. I like not knowing what this mystery food may be. It makes the future more tantalizing.
I've never been to a party when, during a lull in the festivities, someone shouts out, "Let's get some rotis for take out!" Pizza, yes; Chinese food, yes; a run to McDonalds or Burger King, sadly, yes.
I've never been in a group of friends discussing what to eat and someone fake-coughed into their sleeve while exclaiming, "ROTI!!" I haven't met anyone yet who can tell me what a roti is. I must travel in the wrong circles, and yet a roti shop isn't hard to find. They must be selling them to somebody. Again, I must travel in the wrong circles.