Lyric discussion by BusterCornwell 

Cover art for Summertime lyrics by Ella Fitzgerald

Actually this song has been interpreted in two ways. It is a lullaby that could be sang as a mother to their child or as a slave/nanny to a white baby. As a mother to child it implies to the child that this is the only time in their lives that they will live as equal to a baby from wealthy parents, at least until they grow older and realize the harsh reality of the south. Kind of a sad song.