Next Wednesday, 9 September, is the second annual Ding Day. Whenever you see another cyclist, you're supposed to give a quick greeting on your bicycle bell, which they will cheerily return.
My bell is a bit rubbish: a weedy little ting, the sort favoured by hotel receptions so that when guests angrily summon the concierge to complain about their room they just look ridiculous. I want one of those chunky things you crank up with your thumb that sound like a 1950s fire engine.
The problem with ding, as we know, is that it can mean many things. To one person on the canal towpath it's a friendly notification that you'd like to come through, when convenient, hello nice day, how's it going, thanks very much. To the next it's a reason for them to tut, take out one of their iPod earpieces and move grudgingly aside, but only after you've already stopped.
But most pedestrians just don't seem to understand ding. Groups of foreign-language students in Bloomsbury back streets. Strolling families in a side-by-side line that blocks the whole towpath. The sheep-people at pedestrian crossings who keep on crossing even though the little man turned red half a minute ago. They all gawp at you, your bell an incomprehensible smear of Martian noise.
Then I realised: it's all down to tones. Like Mandarin or Cantonese, the meaning of a bicycle bell's ring depends on the intonation and the context.
So here's your guide to the various ways of pronouncing ding, and what it means.