i think this answer
defines the word 'language' as follows: "the whole body of words and of methods of combination of words, used by nation, people, or race; a 'tongue'."
the use of the word "tongue" reminds us that language exists in spoken as well as written form. The word "language" itself is used in many different ways.
Linguists use the term grammar to refer to a subconscious linguistic system of a particular type
feature of human language
1-displacement
2-duality
3-creativity
4-arbitrariness
5-culutral transmission