Lipreading, according to the motor theory of speech perception, is an important component of speech perception. You may be able to learn how to read lips if you pay attention to the movement of your lips and face, as well as the movement of your tongue. Humans perceive spoken words, according to this theory, by recognizing the vocal tract motions with which they are delivered rather than by detecting the sound patterns that speech produces. You may also learn to read lips by reading the lips of others. Most natural speakers of a language can do speechreading without even realizing it. This is due to the fact that they use information from their lips and expressions to help them grasp what is being spoken.
In noisy environments, for example, speech perception increases when the listener can see the speaker's mouth and integrate visual and audible speech information. Another example of how speech perception may benefit not only persons who have hearing loss, but also others who are attempting to communicate with those folks. Many people may not be able to use sign language, therefore speaking clearly and emphasizing their words with their lips may assist those who are deaf. Deaf people who lose their hearing at an earlier age have higher spoken language reading skills. The multi-sensory integration of speech sources is essential for effective communication.
Please watch this video down below, I think it is a huge eye opener