Miriam the Prophetess?

Some have called Moses' sister "Miriam the Prophetess." But why? In The Prince of Egypt, Miriam seems to predict that her baby brother will become the one who helps bring her people out of slavery. "Grow, baby brother," she sings, "Come back someday. Come and deliver us, too." [0:07; seven minutes into the film] Many years later, she confides to him: "God saved you to be our deliverer...and you are, Moses. You are the deliverer!" [0:22; twenty-two minutes into the film]

No, that is not to be found in the Bible, nor is any other explanation of why Miriam has been called prophetess. But you will find a similar story in the Talmud (Mas. Sota 12b) as well as in Midrash Rabbah (Exodus 1:22). There we learn that Rab used to say that Miriam had made just this prediction to her parents while Moses was still a baby. After Moses was placed into the water, his father believed that his daughter's prophecy had been proven false, and gave her a bit of a smack to show his disappointment!