1. a body of words and the systems for their use common to a people who are of the same community or nation, the same geographical area, or the same cultural tradition: the two languages of Belgium; a Bantu language; the French language; the Yiddish language.
2. communication by voice in the distinctively human manner, using arbitrary sounds in conventional ways with conventional meanings; speech.
3. the system of linguistic signs or symbols considered in the abstract (opposed to speech ).
4. any set or system of such symbols as used in a more or less uniform fashion by a number of people, who are thus enabled to communicate intelligibly with one another.
5. any system of formalized symbols, signs, sounds, gestures, or the like used or conceived as a means of communicating thought, emotion, etc.: the language of mathematics; sign language.
American Psychological Association (APA):
language. (n.d.). Dictionary.com Unabridged. Retrieved June 22, 2013, from Dictionary.com website: http://dictionary.reference.com/browse/language