1) Separate from actual performance- what he or she does while producing or comprehending language. In other words, competence is put to use through performance.
2) In actual driving, however, the driver has to relate the Code to a continuous flow of changing circumstances, and may even break it from time to time.
3) An analogy can be made to the Highway Code for driving. Drivers know the Code and have indeed been tested on it to obtain a driving license.
4) Knowing the Highway Code is not the same as driving.
5) In language learning, there is a distinction between competence and performance. Competence is a state of the speaker's mind. What does he or she know?