From
Talking About Words
There is one very special use of quotation marks, which it is useful to know about: we use quotation marks when we are talking about words. In this special use, all varieties of English normally use only single quotes, and not double quotes (though some Americans use double quotes even here). (This is another advantage of using double quotes for ordinary purposes, since this special use can then be readily distinguished.) Consider the following examples:
Men are physically stronger than women.
`Men' is an irregular plural.
In the first example, we are using the word `men' in the ordinary way, to refer to male human beings. In the second, however, we are doing something very different: we are not talking about any human beings at all, but instead we are talking about the word `men'. Placing quotes around the word we are talking about makes this clear. Of course, you are only likely to need this device when you are writing about language, but then you should certainly use it.
Now, Bloke, we've spoken about this . . . ;)
Richard (backing out now as his attempt at what was supposed to be a bit of fun has clearly backfired. He blames himself).
There is a difference between mistakes, errors, trying yet not knowing and just being bloody lazy.