Speech communication stands in contrast to sign language and written language. From the point of view of linguistic evolution, spoken is prior to written language. The writing system of any language is developed or "invented" by its users to record speech when the need arises. Even today, there are many world languages that can be spoken but have no standard written form. Hearing persons acquire their first language by way of spoken language. Writing is learned later. In linguistics, spoken language reveals many true features of human speech while written language is only a "revised" record of speech. Thus linguists' data for investigation and analysis are mostly drawn from everyday speech, which they regard as authentic. Even from the point of view of syntax, spoken language usually has its own set of grammar patterns which sometimes may be quite different from that in written language.
Sign languages have the same natural origin as spoken languages, and the same grammatical complexities, but use the hands, arms, and face rather than parts of the mouth as their place of articulation.