This episode is one of the more seminal pieces of work I've done, both in general and in this series. Producing a show of this breadth completely by yourself poses a few unique problems to the vocally unimaginative ... namely that most of the voices I did sounded the same. Basically, I knew I needed to change Richard's voice and, story-wise, I needed to give him something more to do. Which is why his voice cracks and changes throughout the episode. And why the episode is called "Puberty".
I think that's enough of an explanation, yeah?