I think this topic is wide open. You didn’t say what grade level you are in, but these broad ideas would suit a range of grades, with a depth of detail and analysis suited to your own.
-You could write about your personal feelings about or experience with about English as a course of study. Be sure to decide on what your main point would be, and then pull examples from your past classes and assignments.
-You could discuss the English language itself, and the many other languages it “borrows“ from. A little research would turn up a lot of words from French, German, Italian, and more.
-You could also (with a little research) write about why English is such a difficult language for non-native speakers to learn. It’s considered one of the most difficult to speak and write properly.
-For fun, you could take a look at the words that have been added to the language in the recent past. Every year, the writers of dictionaries, lexicographers, add new ones. Explaining that process or discussing the trends you see in the words that have been chosen would make an interesting paper.
Whenever you are given a one-word topic like this for a paper, part of what your instructor is looking for is how broadly you can look at a subject, how many different angles you can see it from, and how interesting you can make that topic in your paper. Don’t play it safe.