Communicating can be done in various ways including verbally, using cues, gestures, expressions, pictos and symbols.
Children who are mentally retarded most often experience difficulties in communicating, it is difficult to express thoughts with words, even some are not verbal. So visual language will greatly help stimulate language development, recipients, and information providers can understand each other more clearly if language is accompanied by instructions for important words. Picto or pictures, gestures, symbols are all very concrete, children become faster to understand the information conveyed. Facial expressions also indicate the meaning that represents the word, can mean the child is bored, unhappy, angry or sad. Facial expressions can be read clearly so that we can understand each other. All of that is part of communication.