A general superordinate concept for ‘language’ is ‘semiotic system’.

Language is conceived at two taxonomic levels:

  1. At the more general level, ‘language’ is any semiotic system that fulfills the condition of effability.
  2. At the more specific level, a ‘natural vocal language’ is instantiated by languages such as Latin and Vietnamese. This more specific concept is the prototypical instantiation of the general concept.

Language in the general sense is defined as follows: Language is the unlimited creation of shared sense. Just as in the definition of communication, the sharing of sense implies semiosis. The condition of being unlimited implies that these form a system. Consequently, the definition implies that language is a semiotic system.

Furthermore, the definition embodies the condition of effability. It thereby excludes all known non-human communication systems, but allows for the possibility that a semiotic system be found which equals or tops human language in effability. At the same time, this concept does not fix certain conditions which hold for the more specific concept but which need not be fixed for every such system.

For all we know, the requirement of effability entails the property of double articulation: only a semiotic system possessing double articulation can have effability.

A natural vocal language – commonly just called ‘language’ for short – is a language that fulfills the following conditions:

  1. The semiotic system in question is ‘natural’ in the sense of being a general-purpose system that is culturally transmitted across generations by being acquired by children. This excludes, among other things, formal languages.
  2. The perceptible medium that the signs are taken from is acoustic. For human users, this implies that they be produced by the speech apparatus and be perceived auditively. This excludes, among other things, writing and gesture languages.

Semiosis – cognition and communication by signs – is a complex activity characterized by principles regarding the repraesentatum and the message. Some of these principles have a basis in the logic of a semiotic system; others derive from the particular environment in which the system is used.

As to formal structure, units of a semiotic system are objects of the two elementary operations of selection and combination.

As to properties of the semiotic system which depend on its environment, these comprise, on the one hand, the human interlocutors as the subjects of cognition and communication, and on the other hand, the physical and social world in which we live. From the former factor derive, importantly, cognitive and communicative operations which we execute. The latter factor concerns, among many other things, physical properties of the acoustic signals which we transmit.