There is no course for English speakers to learn Thai on Duolingo. Duolingo has been a very useful resource in helping myself and many others gain proficiency in many languages. If this course is developed it could be used by tourists and expats navigate and communicate more smoothly and effectively, people of Thai descent who didn’t have to opportunity to learn it better understand parts of their culture, fans of Thai pop-culture be able to connect with Thai media  on a deeper level widening their perspectives. I think Thai is one of the most beautiful languages and although I have tried many other methods to learning it, I believe a Duolingo course would be the most intuitive way to start.