Headscratchers / Speak Up

• The one thing that I don't understand about this fic: Professor Oak is supposed to be some sort of genius, yet he hasn't taken the time to learn sign language? Isn't that a requirement when you work with children, or at least helpful?
• Why the heck doesn't Ash make use of pen and paper to speak his mind? It's so glaring and unjustified, it reaches Plot Hole levels.