What language did Joseph speak in Egypt? How did he learn it? Was there a common language like Aramaic?
In Genesis 39 part of his ability to find favor must have been the ability to communicate accurately. Similarly, he is shown here as communicating fluently with the Egyptians:
Genesis 40:6-8: And Joseph came in unto them in the morning, and looked upon them, and, behold, they were sad. And he asked Pharaoh's officers that were with him in the ward of his lord's house, saying, Wherefore look ye so sadly to day? And they said unto him, We have dreamed a dream, and there is no interpreter of it. And Joseph said unto them, Do not interpretations belong to God? tell me them, I pray you.