Recording Speech Feedback to Garageband

[itcheroni]

I was wondering if there was a way to record speech feedback onto a track for me to listen on my iphone later. Sometimes my professors give handouts in the form of pdfs. I want to just highlight it and have the computer read it to me but I also don't want to have to sit in front of the computer to listen to it. I've never used Garageband so I've been playing around with it for the past hour and can't figure much out.