Just say "passing" to peds. They will assume it is on their left (or right in England, I guess - do you folks in the homeland pass right or left?). The "on your left" bit requires a ped to make a conscious decision - which way is left? and should I move left or right?

Reminds me of the military saying to the neophyte training to march, "Your OTHER left foot, private"

But, best of all is my bell, which does wonders. If I see no visible physical response to the bell, I will take other avenues of notification. Like, "What did you think I was, an ice cream truck" - well I have never used that, but I have been tempted at times!

When passing a biker, I just say, "Nice Bike" no matter what it looks like. Folks love that, even riding a Huffy.