Because it's a folk song, the "Mama" is often swapped for "Papa," "Grammy," or "Daddy" depending on who is singing. Pop Culture Connections
The song follows a "conditional" structure—each verse introduces a new gift as a solution to the previous one failing.
And if that cart and bull turn over,Mama's gonna buy you a dog named Rover.
At its heart, it’s a song about a parent’s boundless (and slightly humorous) attempt to keep their child happy and quiet.
And if that mockingbird won't sing,Mama's gonna buy you a diamond ring.
And if that diamond ring turns brass,Mama's gonna buy you a looking glass.
They recorded a famous soulful duet version in 1974.
And if that horse and cart fall down,You'll still be the sweetest little baby in town.