Pragmatics studies the factors that govern our choice of language in social interaction and the effects of our choice on others. - David Crystal

The subject matter ranges from subtle forms of intellectual sarcasm and humor to the crudest possible attacks on a person's courage, sexual prowess, or relatives. At one level, attacks may be subtle and indirect, involving allusion and figurative speech; at another, there may be explicit taunts, boasts, name calling, and jokes at the other's expense.

The main metaphor that is used to explain the historical relationship is that of the language family or family tree.

There are the many daily examples of taboo speech, usually profanities or obscenities, that express such emotions as hatred, antagonism, frustration, and surprise. The most common utterances consist of single words or short phrases (though lengthy sequences may occur in 'accomplished' swearers), conveying different levels of intensity and attracting different degrees of social sanction.