Interesting question. I think the reasoning would be just the opposite! Since he grew up in Pharoah's home as Pharoah's son and "Prince of Egypt" he was educated to a very high level, learning all languages, especially the language of an entire nation - the Jewish People - that lived in Egypt and were slaves there to his "father" Pharoah. We have a tradition that the Jewish People maintained their use of the Hebrew language during their centuries of slavery in Egypt. So it was important for the Egyptian leaders to be fluent in the language spoke by the Jewish slave nation.
Besides which, to address the point behind your second question, I don't think an all-powerful God would have any problem finding a way to communicate with one of His creatures, even without the use of any formal language.