What phrase or word do English speakers use when they want to warn you about something for instance?

megalomaniac

It depends on how much time I have. If there is no time I just yell "hey" or "look out", sometimes I even say "ding ding", but if I have a few seconds warning time and I'm approaching a pedestrian from behind I'll often say "I'm on your right" to let them know that I'm about to pass them on the right. Some pedestrians appreciate this and some are completely oblivious.

Rick B

look out. heads up watch out Hey!

Mike

gangway!

Anonymous

"Watch out" sounds a bit more urgent than "look out" but both work.

Anonymous

"On your right" "Behind you" "Coming through" "Beep beep"

p

Careful! or Watch out!

Kiron Kang

Watch out!

WwwdotBibleSelectordotcom

There are different ones and some cultural / local favorites. Some say "Oi!" "Stop!" "Wait!" "Look out!" "Hey!" or "Hey you!"

Keno

If you're looking for something to say that will warn people in front of you about the bike you're riding, you can say any one of these phrases: "Watch out!", "Excuse me!" or "Coming through!" Almost anything works, just so long as you make your presence known. These would be the most polite phrases, though.

charlatan

watch out

busterwasmycat

heads up, coming through. LOOK OUT (when a crash is about to happen).

roberto

yo! watchit say! scuseme,,,, depending the degree of emphasis the speaker wishes to convey loudness, in work a casual reminder 'well you ought to watch this' arms folded & scowling,, body english conveys slight irritation

Anonymous

Watch out Take care keep out of the way. Different people say different things.

sparrow

I'm not aware of a horn that uses a phrase. But English speakers would say: Beware, look out, be careful