Why are human babies so vocal?

Lions and tigers may have deep, knee-quaking roars, but the sound quality is not so different from the grating cry of a newborn human. Now, a new study finds the specially shaped vocal cords and a layer of soft fat allow big cats to roar loudly with little effort.

"The lion roar is a very strong sound," said study researcher Ingo Titze, the director of the National Center for Voice and Speech at the University of Utah. "It's not very tonal, it's rough and grating. There's a purpose to that — it's attention-getting."

Humans have a different vocal-cord anatomy than lions, of course, but their cries are attention-getting too, Titze said. And both babies and lions use their vocal-cord anatomy in their favor to make loud noises without permanently damaging the larynx.

@IA i wasn't referring to Lion cubs i did say lions without the qualifier "cubs" i was trying to make a vocal comparison"

A study was carried out to determine the fine structure of the membranous portion of the human newborn and infant vocal fold mucosae and to clarify how the human vocal fold mucosa begins to grow after birth. Light and electron microscopic observations were made on the vocal fold mucosae excised from human newborn and infant larynges. Our findings are summarized as follows. 1) Reinke's space of the newborn vocal fold is a loose structure composed of ground substance and sparse fibers. 2) Ground substance is abundant and glycoproteins (fibronectin) are present in the lamina propria. 3) In the maculae flavae of newborn vocal folds, fibroblasts begin to form collagenous, reticular, and elastic fibers. 4) In the infant maculae flavae, fibroblasts are activated to become stellate in shape and synthesize extracellular matrices such as collagenous and reticular fibers. 5) After birth, the collagenous and reticular fibers synthesized in the maculae flavae extend toward the middle of the membranous portion of the vocal fold mucosa. 6) Glycoprotein (fibronectin) determines the orientation of collagenous and reticular fiber deposition. 7) Glycoprotein (fibronectin) decreases with the increase of the fibrous components in Reinke's space. 8) Elastic fibers increase after collagenous and reticular fibers appear in Reinke's space. 9) Much hyaluronic acid (glycosaminoglycan) is actively produced in the infant maculae flavae. 10) The collagenous and reticular fibers serve as stabilizing scaffolds for the other extracellular matrices, such as elastic fibers and glycosaminoglycan. During infancy, the extracellular matrices synthesized in the maculae flavae appear in the membranous portion of the vocal fold, each at a different time, so as to initiate the 3-dimensional formation of the vocal fold mucosa.

Seems to me the above statements haven't answered your question. To part A of your question, yes during the holocaust some mothers did smother their children to avoid detection by TE nazis. Part B, the human child is vocal because unlike any wild mammal it's not born with the capability to search for its food, it needs help up until it can walk(technically speaking). If humans could walk at birth, I'm sure eventually babies would adapt to looking for their own food.

The video doesn't show on the page for me. But to answer seriously, when I was a teenager, it was recommended that vocal lessons and exercises should usually not be started until the age of 16, when the diaphragm, voice box, and nasal cavity are fully developed. Otherwise the singer could prematurely affect the physical potential for singing development and longevity.

Because they are humans.

Dogs communicate by smelling each other's butts. Monkeys communicate by smelling each other's armpits. Whales sing songs that can be heard all over the world. Humans talk words at each other.

Reasons for the differences involve religion, and we have quite enough of that already.

In the wild, predators would love to hear loud babies.

But humans really have no predators,

so evolution has probably allowed us to keep producing loud babies.