I did the audiobook version of this. It's quite long and I'm not sure it really needed to be as long as it was. I was enjoying it for the most part, but I found it very unnecessary to mimic random accents. This isn't a fictional story where you're trying to show different voices for different characters. It wasn't very consistent either, which made it seem even more unnecessary. An English accent, German accent, French accent?
it was 100% unnecessary to mimic an "ASL speech pattern." You can say someone's speech improved without mimicking a speech impediment.