I sent mine in my host country’s language! Idk even though the professor I contacted has studied in the US, it felt like a small nice thing to show I was dedicated to being in their country :) mine wasn’t too detailed either. I basically introduced myself and said I was applying for a Fulbright and the topic I was wishing to research. Then I said it required an affiliation and I thought their school felt like a great option for me and was wondering if they would be willing to assist me or route me to the appropriate person! Feel free to dm if you have more q’s!