Что это?

A small electronic device worn behind the ear that makes sounds louder. It allows a person who is hard of hearing to participate more fully in communication and activities. A cochlear implant consists of an external portion behind the ear and a second portion that is surgically placed under the skin. It can help provide a sense of sound to a person who is profoundly deaf or severely hard of hearing.

Где его найти?

Behind the ear.

Как мне его использовать?

When communicating with people who are hard of hearing, it can help to face the person directly without a barrier near your mouth (hands, gum, etc.); speak clearly, slowly, distinctly but naturally (without exaggerating mouth movements—this can make it more difficult for those who read lips to understand what you are saying); stay in good lighting; and use body and facial expressions in addition to your verbal communication. You may need to repeat, rephrase, simplify, or write down what you are saying. Be aware of the listening environment and be patient with yourself and others.