Karl Popper tried to analyse language and its functions. His teacher, Karl Bühler, had already come up with a distinction of three different functions of language. Popper adopted this distinction and added an additional fourth function of language. These four functions are relevant in any conversation taking place. Sometimes they can be seen in isolation, and at other times, they can overlap, resulting in some or even all of them being part of a single statement or utterance.
The first function to mention is the expressive function. Here, language is used to express feelings or emotions, such as anger or joy.
The second function is the signal function. While the expressive function is mainly concerned with expressing the speaker’s own feelings, the signal function communicates a message to its audience that is intended to provoke some kind of reaction. The statement “I am cold,” for example, could be seen as expressive, as it states how the speaker feels. In addition, it could also be seen as a signal, as the speaker might implicitly ask the other person to perhaps close the window or turn the radiator up by stating that they are feeling cold.
The third function of language is the descriptive function. This is almost the opposite of the expressive function. The expressive function is used to verbalize an internal feeling or perception. It is therefore fairly subjective. The descriptive function, on the other hand, is used to describe something external, which makes it an objective, verifiable statement. An example of this would be “My car is red.”
The fourth function is the argumentative function. Here, a statement is made with the view of inviting a response that either agrees or disagrees with the statement. “The Beatles are the best band ever” would be a good example here, as the other person would be expected to respond to this statement either by agreeing or disagreeing.