How to practice reading founding documents in the SAT reading section?

Hello!
I am an incoming junior in high school, and I am preparing for the SAT. When it comes to the reading section, I am very comfortable with science, social science, and fiction; but the one founding document, such as a speech about women’s suffrage, civil rights, etc. troubles me the most, because the language that it uses is very archaic and difficult to understand for me. Are there any ways that I can practice reading this type of passages? What documents should I read to improve? Or are there any books that you would recommend?
Thank you!