Back in high school, to study for my German III final I only spoke German for an entire week. I didn’t speak a word of English. As a result, my mom and little brothers kind of understand German. Basically the only people that really understood me that whole week were other students in German class and the German teachers.
That being said, it was worth it. I got a ton of speaking practice and I was able to solidify all the concepts in my mind so I had them in the front of my mind (do people say the front of my mind?) when it came time to take the test. There was a speaking portion and a writing portion. For the speaking portion the only thing that I got wrong was I said “an” instead of “auf”, so it slightly changed the meaning. I got the highest grade in the class. I would recommend this study method to anyone who’s nervous about any finals coming up in a foreign language class, or if you want to have a fun challenge for a week to really increase your speaking skill level.
Maybe if you have a math final, only respond in equations—only kidding.
Hope this helps!