The first three years of life is very critical for a person to develop speech and language skills. The brain is still developing and figuring out how to make sense of the sounds heard by the baby. During this critical phase, the brain is able to easily learn language. If the baby is repeatedly exposed to sounds and the language spoken by the people around, the baby starts learning how to speak the same language. This is what happens in the case of babies with normal hearing. After 3 years, the brain is nearly matured (80% developed), and it becomes more difficult to learn language if the child has not been exposed during the critical period (0 – 3 years). This is what happens in babies with hearing loss who have not been fitted with a hearing aid or have undergone cochlear implant surgery during this time window.

Once a baby (aged 3 years or less) is fitted with the hearing aids appropriate for its degree of hearing loss, the hearing aids amplify the sounds loud enough for the baby to hear using its residual hearing. Residual hearing is defined as the amount of hearing a child with hearing loss has.

The amplified sound vibrations are converted into electrical signals which are then sent to the brain.

With the help of early intervention that includes a comprehensive and intensive training regimen of 3-4 years, commonly referred to as Listening and Spoken Language (LSL) Training, or SALT (Speech and Language Therapy), the baby’s brain gradually learns how to associate these electrical signals with meaning and records it in memory. It is very important that the baby be consistently exposed to sound and language by wearing hearing aids or cochlear implants, throughout all waking hours, for the training to be effective.

After the baby starts being trained how to recognize sounds and words, the baby now tries to reproduce the same sounds by speaking. Since the baby speaks whatever it hears, the quality of feedback the baby receives, and in turn, its speech, is heavily dependent on the quality of hearing and the quality of training.