How to read out loud into a microphone better?

I'm studying the play "Hamlet" at school and I need to learn a whole bunch of quotes. I want to record myself reading them and then play the recordings over while I'm studying, but whenever I talk into the microphone I develop a lisp and start mispronouncing words left right and center. I keep making mistakes that I wouldn't make when reading in front of my class. My voice itself changes and it sounds unclear and crackly. Any tips on how I can overcome this?