In the formal paradigm a language is regarded as an abstract formal object (e.g. as a set of sentences) […]. In the functional paradigm, on the other hand, a language is in the first place conceptualized as an instrument of social interaction among human beings, used with the intention of establishing communicative relashionships. Within this paradigm one attempts to reveal the instrumentality of language with respect to what people do and achieve with it in social interaction. A natural language, in other words, is seen as an integrated part of the communicative competence of NLU (natural language user).
- Dik (1989), a pag.2-3