The text was completely readable for me, viewing on an iPad (not even fullscreen).
Xcode is the standard IDE used for all Apple software development - 99% of people viewing a video like this would know that, as its so elementary. I'm surprised you didnt also expect the author to define what a terminal window was and what Objective C is. A google search would have yielded the answer in less than 2 seconds.
Overall I found the video very intersting and its the first time i've seen audio being iteratively produced in real time with code, thanks for taking the time to produce it.