Restaurants in Goa offering traditional Goan cuisine serve vindaloo with pork, which is the original recipe. The dish was popularized by Goan cooks (whom the British favoured because they had no issues in kitchens and bars when handling beef, pork or liquor) in the British establishments and the ocean-going liners. This dish is still available on the P&Oliners in its original "pork vindaloo" form. However, restaurants outside Goa serve vindaloo with chicken or lamb, which is sometimes mixed with cubed potatoes. Even though the word aloo means potato in Hindi, traditional vindaloo does not include potatoes. This is because Hindi is not the only language spoken in India and not spoken by the majority of Indians. The dish hails from Konkan region which speaks Konkani.

Source:[http://indiafoodnetwork.in/food-stories/veras-fish-vindaloo-parsi-one-forgot/]