I spent a week in Bangalore in May -- as far as I could tell, a horn honk means:

- Don't cut me off
- You just cut me off
- I am cutting you off
- You're in my lane
- I'm sharing your lane
- Watch out; don't walk in front of me
- I am happy
- I am sad
- Hi!
- I haven't honked in at least 20 seconds

Walking down the street listening to the horns is definitely part of immersing yourself in the experience of being there -- and prepares you for "crossing the street", which I did several times a day because the hotel was across Old Airport Road from the office building. Basically like playing Frogger, only with fewer lives. Fortunately the traffic, while very very heavy, goes relatively slowly and has some gaps, and the drivers are paying attention even if they don't look like they are, and generally avoid collisions...