Only the other day I came across the expression ‘physical literacy’. Apparently it means being able to run and jump and catch and so on, and the phrase has been in use for five years at least. I remember when the word ‘oracy’ came in – it must have been in the 80s – and we all had to learn what it meant and make sure it was attended to. No doubt there are more –acies on their way, and we shall have to deal with them when they turn up. I suppose the suffix means ‘the capacity, opportunity, or vocabulary to talk about something we all used to do without thinking about it’.

Some of these terms will be more useful than others. But visual literacy is an idea that both makes sense and is interesting to talk about. How do we read a picture? How do we read the graphic symbols that we see in every advertisement, on every screen, in every comic? Unlike words and sentences, these things don't have to be taught and learned (or tested – yet): they don't seem to need any pedagogy at all.

Take a little visual convention like the difference between the speech balloon and the thought bubble. Did we have to be taught what they meant? As far as I can remember, I worked it out for myself, and thought at once how clever I was. Somewhat later I thought how clever the person who invented it was. One of the ancestors of the speech balloon was the long scroll emerging from the mouth of Thomas Cranmer being burned at the stake in the illustrations to Foxe's Book of Martyrs (1563), but no doubt there were others. It works because it's so easy to understand.

Or take a short wavy line. What does that mean? It's not like a word, whose meaning we can look up in a dictionary. But in the context of one frame of a comic it could depict a single hair on a bald head, in another the sound of a bird singing, in yet another the powerful aroma of a gorgonzola cheese, in one yet further the disturbance of the air caused by someone running very fast.