Instead of looking at types of sounds as the source of human speech, we can look at the types of physical features humans possess, especially those that may have supported speech production.
Our ancestors made a major transition to an upright posture, with bi-pedal (on two feet) locomotion. This really changed how we breathe.
Other physical changes have been found. The reconstructed vocal tract of a Neanderthal man from around 60,000 years ago suggests that some consonant-like sound distinctions were possible.
Around 35,000 years ago we start to find features in fossilized skeletal structures that resemble those of modern humans.
Teeth and Lips:
Human teeth are upright, not slanting outwards like those of apes, and they are roughlyeven in height. They are also much smaller.
It very helpful in making sounds such as f or v.
Human lips have much more intricate muscle interlacing than is found in other primates and their resulting flexibility certainly helps in making sounds like p, b and m.
Mouth and Tongue:
The human mouth is relatively small compared to other primates and can be opened and closed rapidly.
It is also part of an extended vocal tract that has more of an L-shape than the straight path from front to back in other mammals.
Unlike other primates, humans have a shorter, thicker and more muscular tongue that can be used to shape a wide variety of sounds inside the oral cavity.
Humans can close off the airway through the nose to create more air pressure in the mouth with more intricate muscle interlacing in the lips and mouth, capable of a wider range of shapes and a more rapid and powerful delivery of sounds produced through these different shapes.
Larynx and Pharynx:
larynx: the part of the throat that contains the vocal folds, also called the voice box.
The human larynx differs significantly in position from the larynx of other primates such as monkeys.
Pharynx: the area inside the throat above the larynx.
In the course of human physical development, the assumption of an upright posture moved the head more directly above the spinal column and the larynx dropped to a lower position. This created a longer cavity called the pharynx.
Above the vocal folds, which acts as a resonator for increased range and clarity of the sounds produced via the larynx.