WE ARE so used to reading about the same old topics, in manuals of English usage split infinitives, will and shall, between you and me, and the like that it's easy to forget there are hundreds of usage issues which receive next to no attention at all. An article by Betty Lou Dubois in a recent issue of Language in Society has focused on one of them. It's an analysis of the way scientists use numerical expressions in an imprecise way, as they talk about their subject, and it reminds me that linguistic imprecision is a topic about which we could usefully be more precise. Imprecision, like ambiguity and repetitiveness (see ETl4), is one of those notions which tends to be immediately and unthinkingly condemned. If someone is being imprecise, that must be bad. But it turns out, when we look carefully at the way people talk and write, that there are numerous contexts where a modicum of imprecision is desirable or even essential. Moreover, most of it is rarely noticed. This is a point I have always suspected for everyday informal conversation. What I found particularly interesting about Dubois' article was to see how frequent and important the phenomenon is in scientific expreSSIOn. What Dubois has done is classify all the imprecise expressions (or 'hedges', as these are often called, in the linguistics literature) found in a series of slide talks given at a professional biomedical meeting. There were a large number of them, and they displayed a considerable range. About was by far the commonest (as in about 10 per cent of the animals developed the virus), but there were many others. Most of the hedges preceded the figure: almost 10%, approximately 10%, around 10%, close to 10%, nearly 10%, of the order of 10%, some 10%, somewhere around 10%, something like 10%. Some followed it: 10% or more, 10% or so, 10% plus or minus, 10%nearly. And there were several cases where more than one hedge was used in the same phrase: something of the order of 10%, about a little over 10%, about 10% or so, around 10% or more. I suspect there are limits to this process, though I don't know what they are. More than two hedges are unlikely, to my mind, though I don't suppose we can completely rule out the possibility of such phrases as 'something of the order of about 10% or so, more or less'! The hedges in Dubois' article are only a fraction of what is available in the language. A few moments' reflection brings to mind the following, in addition to the above: roughly, practically, all but, in the region of, thereabouts, hard on, well nigh, as good as, within an ace of, verging on, virtually, perhaps, usually, invariably, sort of, kind of ... There must be hundreds more. They range from the highly formal (such as circa) to the highly informal (such as say we'll need something for the hotel, £10, say ... ). Why do we use hedges? It isn't just a matter of carelessness, laziness, lack of memory, lack of knowledge, or some other deficit in our performance. If you ask me how many people were at the meeting, and I say about 50, this level of precision suffices for the casual purpose of the exchange. Indeed, if I were to say 53, it would suggest that I was making a particular point. (This is a real example, in fact: the other evening, we had put out 50 chairs for a meeting, having previously wondered whether that would be enough; afterwards, I asked how many people had been present, and one of the organisers said 53, in disgust he was the one who had had to get three extra chairs from another room!) People don't want to be precise all the time. It would be intolerable if every time we spoke we had to recall our behaviour with mathematical precision. A 'What did you buy?' B 'Oh, apples, bananas, cabbages, and so on'. This is enough for A to be informed of