The vestibular system is the first sensory system to develop in utero. It starts to develop early in the first month even visible from 17 days. Between four to six weeks the vestibular and cochlear systems become differentiated. And at seven weeks, the auditory ossicles start to grow.
At 16 weeks gestation, the middle and inner ears are complete and have an adult size. Its neurological organization is well underway. At 5 1/2 months, the cochlear nerve is myelinated. Myelination to the temporal lobe is started and will be completed at birth.
Active listening starts at 24 weeks. It starts to develop early in the first month. Mature synapses are found between 24 and 28 weeks. Dr Tomatis felt that this early listening played a significant role in inviting the fetus to communicate, develop language, and learn. The journey toward language starts not in the nursery but in the womb, where the fetus is continually bathed in the sounds of its mother’s voice; hence, his mother’s tongue.