'Difficulty' in the Bible

But Moses replied to the Lord, "If the Israelites did not listen to me, then how will Pharaoh listen to me, since I speak with difficulty?"

But Moses said before the Lord, "Since I speak with difficulty, why should Pharaoh listen to me?"

He jammed the wheels of their chariots so that they had difficulty driving, and the Egyptians said, "Let's flee from Israel, for the Lord fights for them against Egypt!"