The role of Language...Why do I want to teach English?

What is language? Has anyone ever thought about it in depth other than the linguists?
Language is :

1. A means of communication
2. The channel through which we express our thoughts and emotions
3. Something which shapes the way we think? The grammar structures and vocabulary seems to have an impact on the way we behave. Or is it the other way?
4. A medium to another's culture and beliefs
5. A medium to see the world from a different perspective
6. A medium to advancement and development
7. A medium to self discovery through words
8. Enjoyment and reflection through words
9. To create an impact on others for social causes
10. To preserve one's culture and traditions
11. Language is one medium to knowledge as knowledge is often encapsulated in alphabets. Without the ability to comprehend words and its meaning or, in other words, syntax, we close the door to knowledge.