When described as a system of symbolic communication, language is traditionally seen as consisting of three parts: signs, meanings and a code connecting signs with their meanings. The study of how signs and meanings are combined, used and interpreted is called semiotics. Signs can be composed of sounds, gestures, letters or symbols, depending on whether the language is spoken, signed or written, and they can be combined into complex signs such as words and phrases. When used in communication a sign is encoded and transmitted by a sender through a channel to a receiver who decodes it (a signal).

Some of the properties that define human language as opposed to other communication systems are: the arbitrariness of the linguistic sign, meaning that there is no predictable connection between a linguistic sign and its meaning; the duality of the linguistic system, meaning that linguistic structures are built by combining elements into larger structures that can be seen as layered, e.g. how sounds build words and words build phrases; the discreteness of the elements of language, meaning that the elements out of which linguistic signs are constructed are discrete units, e.g. sounds and words, that can be distinguished from each other and rearranged in different patterns; and the productivity of the linguistic system, meaning that the finite number of linguistic elements can be combined into a theoretically infinite number of combinations.[16]

The rules under which signs can be combined to form words and phrases are called syntax or grammar. The meaning that is connected to individual signs, words and phrases is called semantics. The division of language into separate but connected systems of sign and meaning goes back to the first linguistic studies of de Saussure and is now used in almost all branches of linguistics.