Did Moses Stutter?

In the first parsha of Exodus, God speaks to Moses at the burning bush after his flight from Egypt, announcing that He will liberate the Israelite slaves and instructing Moses to return to Egypt to lead the mission. Moses is reluctant to accept, and from Moses’ own mouth we hear the reason for his reluctance: He is kaved peh, heavy of mouth. God seems to acknowledge the impediment, assuring Moses that He “will be with your mouth and teach you what to say.” Moses begs God to send someone else; God is angry but finally agrees to send Moses’ brother Aaron with him as his spokesman in Egypt. Aaron performs this function until, toward the end of the Five Books, Moses gains a stunning eloquence.

http://www.jewishideasdaily.com/content/module/2012/4/12/main-feature/1/the-stuttering-servant/e