How are hearing and speaking connected?

Sound waves can be created by many different things, such as a piano string vibrating and the vibrations of the vocal cords in our throat.

How well we can hear something depends on:

• Volume (sound pressure level) – measured in decibels (dB)
• Pitch (frequency of the sound waves) – measured in hertz (Hz)

Our hearing is particularly sensitive to frequencies generated when we speak. As a result, we can understand spoken words and sentences even at relatively low volume.

Children learn the language spoken around them by listening and “parroting” – and then hearing their own voice. They can even learn several languages and speak them fluently later.

But they can only learn language in this effortless way if their hearing works, too. If a child born with severe hearing loss or deafness doesn't get the right treatment, their speech and language skills will develop more slowly, or not at all. This can affect their ability to learn, as well as their general personal and social development.

The term “deaf and dumb” is no longer used today because it's often found to be offensive.

If people with hearing problems start using a hearing aid or prosthesis (cochlear implant) early enough, they will often still manage to pick up acoustic impulses like spoken language, and then learn to speak themselves. Even if you can't hear properly and the problem isn't treated, you can learn how to communicate in other ways. One example is sign language: This involves expressing words and sentences using signs and movements made with your hands, as well as facial expressions. So you see the language rather than hearing it.

Another form of communication is lip-reading. Here deaf people can work out what other people are saying by closely watching their mouth when they speak. With targeted speech therapy, they can also learn to make sounds with their mouth and throat, and then communicate with spoken language – with some limitations.

People who can lip-read can also communicate with hearing people who don't know sign language. But it's difficult to say which of these two types of communication is better suited.