Lip-reading, also known as lipreading or speechreading, is a technique of understanding speech by visually interpreting the movements of the lips, face and tongue when normal sound is not available. It relies also on information provided by the context, knowledge of the language, and any residual hearing. Lip-reading is not easy, as this clip demonstrates. Although ostensibly used by deaf and hard-of-hearing people, most people with normal hearing process some speech information from sight of the moving mouth.