Kind of inspired by that thread: https://www.reddit.com/r/forza/comments/x055kz/use_your_honk/
Since there is only 2 spaces in quick chat, which I use for “sorry” and “nice driving”, is there any “beeping language”?
For example I use:
2 short beeps - (usually at the end of race) as GG or good race
One long beep - for someone who doesn’t know how to drive or not leaving space
Many short beeps - when I’m overtaking, that one is more for Trial
Do you have any other signals?
I also use short beeps when passing in the trial.
Aside from that I will turn on siren when I’m behind someone in online racing to make them panic.
None of your honking business!
But seriously, I almost never use the horn, though I do appreciate being honked at as an approach warning in Trials since I almost never look behind me.
Mostly in “trials” but if a faster car (team mate) is coming up on me, i’ll move over a give a couple of short toots in way of acknowledgement that i’ve seen them as I let them past.
problem I find in Trial is even if I hear a horn I’m too slow to do anything (well, D or C maybe) and if I do I lose at least 11 places and probably take out other people along the way
I only use the horn in the Arcade where that is one of the tasks.
My experience is typically in the trial when you have multiple sound effect horns constantly blaring for no apparent reason other than to be annoying, which they are quite effectively.
I may give a couple taps after a free roam race as in “good race & see you later” then I’m out 
Honk if you’re hooning.
I use the horn in trials and tours to let people know when I’m passing or to signal them to pass me.
I often give a couple of short honks to others players in freeroam, on the rare occasions I see anyone.
Fun topic!
I also give a quick double-beep in free roam as a friendly ‘hiya’ while rolling past others.
At one point I had some folks following me around in free roam as I drove from place to place. I used the horn double-tap as a way to signal when I was ready to roll out after choosing the next location and vehicle.
When taking a big jump I might go horn-bonkers as if warning people to look out, whether anyone’s around at the time or not. Incoming auto!
The rare times I’m playing cooperatively such as Tours or Trials I will occasionally use it to signal passing, usually a quick single beep to acknowledge those who are giving me notice as they’re trying to pass. Sometimes I give a quick tap of the brakes to give everyone space as well so it kind of doubles as a notice I’m about to take part in the shifting of positions.
When racing solo against drivatars it is strictly an instrument to express my rage at them thoughtlessly shoving me around. I know it doesn’t do anything useful but I still feel the need to call them out on their awful behavior. If the game allowed for pit maneuvering I’d be doing that, instead.
One or two short beeps is just “Hi”, or “Nice job”
One long beep is when I call someone out for being an idiot and not knowing how to drive
None, off, don’t even want them in the game. Don’t even use it much irl.
i use the horn to say hello occasionally. if i try to use it in a race my view gets skewed and i usually wind up crashing, so it only gets used outside of events.
In The Eliminator i use the “Qwak Qwak” Duck horn when a rival or myself hits a object.
In The Trail i am to use the “Cucko” Horn before, during and after the first corner.
I let my wololo fly freely.
Only real gamers know of the wololo days
car horn is vital aspect of creative expression!
I ram honkers, honking is a micro agresion that I will kindly respond to with some real push you into a wall/out of bounds agresion.
You honk at me and you already have lost.
So that is how you win races in Eliminator? 
324 so far
I dare you to honk at me