Speakers use a finite set of rule to produce and understand an infinite set of possilbe setences. These rules are part of the grammar of a language, which develops when you acquire the language and includes the sound system (the phonology), the structure and properties of words (the morphology and lexicon), how words may be combined into phrases and sentences (the syntax), and the ways in which sounds and meanings are realted (the semantics).
Και αν πέσουν αυτά που διαβάζουμε, εμένα να μη με λένε Ουρανία.