It is said in the Bible that Miriam and Aaron were prophets in their own right: that is, their vision was not dependent on that of Moses.
It becomes apparent, too, that Miriam was the leader-prophet of the women of Israel, while Aaron was the leader of the men.
This is evident even after the crossing of the Red Sea, following the great song (Exodus 15) which Moses sang in honor of all Israel, and Miriam separately organized the women in response, with "timbrels and with dances" (Exodus 15:20).
The role of a women's chorus is a common phenomenon in Middle Eastern culture and may be of even greater antiquity than the male chorus.
As in the Song of Deborah, the singing of women, usually accompanied by timbrels and dancing, gave expression to war, battle, and miracle.
Frequently the song was led by a solo singer, who would compose the litany as she went along.
The singer was, therefore, first and foremost a poetess whose task was to articulate and summarize a historical experience or to arouse the nation to cope with a present or forthcoming challenge.
–Rabbi Adin Steinsaltz
From Biblical Images by Rabbi Adin Steinsaltz