Rebbi — Rabbi Yehudah HaNasi, the compiler of the Mishnah (the earliest code of rabbinic law) — offers an alternative reading that slightly adjusts the ages of the miraculous singers at the Red Sea. Where Rabbi Yossi understood olelim as unborn infants in the womb, Rebbi identifies them as infants who have already been born but are still very small — young children who are "outside" their mothers' bodies.
His proof texts are precise. "To cut off the olel outside" (Jeremiah 9:20) — the word olel here refers to a child in the streets, already born and walking about. And "Olelim begged for bread" (Lamentations 4:4) — children old enough to feel hunger and ask for food, but still too young to fend for themselves. These are toddlers, perhaps, or very young children capable of simple speech but not yet independent.
Yonkim, in Rebbi's reading, are those still nursing at their mother's breast — the same definition as Rabbi Yossi's. The verse from Joel about "suckers of the breasts" confirms this identification.
Despite the slight difference in defining olelim, Rebbi arrives at the same conclusion: "These and those opened their mouths and chanted song before the Lord." At the splitting of the Red Sea, both the toddlers and the nursing infants sang. Rebbi's version grounds the miracle in slightly more natural terms than Rabbi Yossi's — these children had at least been born and possessed mouths capable of sound — but the supernatural element remains. Infants and toddlers who could barely form words produced coherent song praising God.