Writing is a medium of human communication that represents language and emotion with signs and symbols. In most languages, writing is a complement to speech or spoken language. Writing is not a language, but a tool used to make languages be read. Within a language system, writing relies on many of the same structures as speech, such as vocabulary, grammar, and semantics, with the added dependency of a system of signs or symbols. The result of writing is called text, and the recipient of text is called a reader. Motivations for writing include publication, storytelling, correspondence, record keeping and diary. Writing has been instrumental in keeping history, maintaining culture, dissemination of knowledge through the media and the formation of legal systems.
As human societies emerged, the development of writing was driven by pragmatic exigencies such as exchanging information, maintaining financial accounts, codifying laws and recording history. Around the 4th millennium BC, the complexity of trade and administration in Mesopotamia outgrew human memory, and writing became a more dependable method of recording and presenting transactions in a permanent form. In both ancient Egypt and Mesoamerica, writing may have evolved through calendric and a political necessity for recording historical and environmental events.