Ever since humans have inhabited the earth, they have made use of various forms of communication. Generally, this expression of thoughts and feelings has been in the form of oral speech. When there is a language barrier, communication is accomplished through sign language in which motions stand for letters, words, and ideas. Tourists, the deaf, and the mute have had to resort to this form of expression. Many of these symbols of whole words are very picturesque and exact and can be used internationally; spelling, however cannot.
    Body language transmits ideas or thoughts by certain actions, either intentionally or unintentionally. A wink can be a way of flirting or indicating that the party is only joking. A nod signifies approval, while shaking the head indicates a negative reaction. Other forms of nonlinguistic language can be found in Braille (a writing system for the blind, composed of raised dots to be read with the fingertips), signal flags, Morse code, and smoke signals. Road maps and picture signs also guide, warn and instruct people.
    While verbalization is the most common form of language, other systems and techniques also express human thoughts and feelings.