Exactly what is it that we cannot say?

Keith Allan and Kate Burridge teach linguistics at Monash University, and their book has a distinctly Australian flavour. The technical term for the subject they mainly deal with is linguistic "avoidance". Unfortunately, they jazz it up under the popular label "taboo", which is strictly only one variety of the phenomenon. They end up dumbing down "taboo", so the term takes in virtually any form of disapproval. This does less than justice to taboo as anthropologists understand it and conflates distinctions between different aspects of normativity in language. Along with the dominance of English-language examples, the book provides a very ethnocentric framework, conveying the impression that taboos of the kind Captain Cook first reported are no more than primitive and irrational versions of the same inhibitions observable in "civilised" (that is, Western) societies.

Even the term "forbidden" in the title is misleading. Practices may be disapproved of, deplored and denounced, but not forbidden. Allan and Burridge claim to offer "an interesting perspective on the human psyche". But they do not understand the semantic subtleties of their subject. Any perspective that can suggest that the taboo on Tahitian women eating with men is comparable to the Western disapproval of "using your fingers instead of cutlery when dining in a restaurant" must have something seriously wrong with it.

They count virtually every infringement of law, convention or superstition as "taboo". This allows them to make such implausible claims as that "restrictions on language and weapons have the same motivation". Anyone who has not by this point put the book down will find chapters with alluring titles such as "Sex and bodily effluvia". As for nutrition: "Food and drink are just shit and piss waiting to happen." Freud is mentioned once but never discussed.

Most of the book is scissors and paste. The only original research the authors have done seems to consist of counting the number of times the words "die" and "death" appear in the "In memoriam" notices published in one issue of a Melbourne newspaper and circulating a questionnaire to students and colleagues asking questions such as whether sweat is more revolting than menstrual blood or tears more revolting than hair clippings. The results are duly quantified as "revoltingness ratings" (sic).

The seamier side of language has always exerted a powerful fascination for a certain type of mind. According to the authors, "when we look at the exuberance of expressions that proliferate around the forbidden, it is also clear that we are having a lot of fun". But the jollity evaporates with the introduction of classificatory terms such as "euphemism", "dysphemism" , "orthophemism" and "X-phemism".

The last two are original coinages of which the authors are particularly proud. The former means "direct or neutral expressions that are not sweet-sounding, evasive or overly polite (euphemistic), nor harsh, blunt or offensive (dysphemistic)"; the latter includes not only euphemisms and dysphemisms but orthophemisms.

The trouble with extending the province of "taboo" in this open-ended way is that the topic rapidly becomes unmanageable. The authors discuss censorship and self-censorship, blasphemy, impoliteness, jargon and have a whole chapter on political correctness. But what you may and may not say in Western societies also has some well-documented legal aspects, such as the laws of libel and trade descriptions, about which the authors say nothing.

There is a feeble chapter on linguistic purism, which consistently puts the cart before the horse. Puristic attitudes, we are told, "are driven by an ideology of the standard language". But linguistic purism existed centuries before the concept of a "standard language" was even formulated.

The most interesting questions about linguistic preferences are never discussed. There is no mention of the most widespread linguistic "taboo" in human society: that against falsehood. The naive notion that verbal avoidance is merely the transference to a linguistic level of aversions to certain objects and practices is open to question. The most obvious counterevidence is that terms for "taboo" items are not themselves automatically avoided.

In short, this book never tackles the underlying nature of the complex relationships between verbal avoidance and non-avoidance. As Lévi-Strauss noted years ago, it is no use blandly explaining cultural phenomena by reference to social "attitudes": that merely disguises a failure to analyse the "attitudes" themselves.

Roy Harris is emeritus professor of general linguistics, Oxford University.