Language is a system of arbitrary, vocal symbols which permit all people in a given culture, or other people who have learned the system of that culture, to communicate or to interact.
(Finocchiaro, 1994: 8)
Language is a system of communication by sound, operating through the organs of speech and hearing, among members of a given community, and using vocal symbols possessing arbitrary conventional meanings.
(Mario A. Pei, 1996: 14)