There are at least three different basic functions of language:
Informative – words can be used to pass on information
Expressive – words can be used to evoke an emotion that is not a direct result of their meaning
Performatory – words can be as a kind of symbol / action in and of themselves
Language functions in many different ways. Its most familiar function is informative, i.e. it transmits information. But it also operates expressively, when we attend to the feelings evoked by the words rather than just their meaning. Poetry often combines the informative and the expressive:
The fair breeze blew, the white foam flew The furrow followed free We were the first that ever burst Into that silent sea.
Samuel Taylor Coleridge, “Rime of the Ancient Mariner”
When Ajax strives some rock’s vast weight to throw, The line, too, labors, and the words move slow; Not so when swift Camilla scours the plain, Flies o’er th’ unbending corn, and skims along the main.
Alexander Pope, “Essay on Criticism”
I sprang to the stirrup, and Joris and he; I galloped, Dirck galloped, we galloped all three.
Robert Browning, “How They Brought the Good News from Ghent to Aix”
In these verses the rhythm and sound of the words are expressive in themselves. Language is also used expressively in prayer; and when a man whispers “sweet nothings” into his wife’s ear, or tells her she looks “scrumptious”; and in such sounds as “wow!” and “scram!”; and when a politician or preacher or salesman uses words to evoke emotional responses.
A third area of language is the ceremonial. Here the words are not necessarily either informative or expressive, but performatory, they are an action in themselves. Examples are “I thank you, apologize, warn, greet, guarantee, promise, welcome,” etc. These words are complete speech acts. They do not describe the acts of thanking, apologizing, warning, etc., but instead are those very acts. They are not propositions which can be true or false. If a man says, “I bid you good morning,” that does it (even though he may hate you). The use of language solely to establish social relations is called “phatic communion” by Malinowski; in our culture, “hya doin’?” exemplifies this. In all of these performatory utterances, as in oaths, incantations, passwords, and rituals, there must be no change in the exact words. If you are asked whether you take this woman to be your lawful wedded wife, and you answer “yes” instead of “I do,” you may turn out not to be married. In its performatory sense, language is like any other gesture or symbol: the handshake, the military salute or the gestures of the baseball umpire. Austin estimates that there are over a thousand performatory verbs in English.
Language also functions to tell a story, to declaim, to hypnotize, to play a part, to imagine, to soothe, to ask, to deceive, to demonstrate one’s feelings, and in endless other ways.
So when it comes to talking about what language does, as a TOK student, you need to be aware that language actually functions in a variety of ways, each of which may have slightly different rules of behaviour.