The lexicographic nerds who compile the OED are sworn to a vow of silence. In an open-plan office that counts as a sterile environment, colleagues with adjoining desks are forbidden even to whisper and must email each other to communicate; a soundproof glass booth is set aside for those who must resort to speech. But the language they deal with prattles and jabbers in a variety of cosmopolitan accents and pidgin tongues. Sarah Ogilvie's "words of the world" erupt in a din like that of world music. Though all theoretically English, these global words are played by instruments that include the bagpipes, the Welsh harp, African drums, Arab flutes and the didgeridoo.

Ogilvie's book  once you get past its tiresome academic apparatus of bar graphs and pie charts  is about the paradox of an insular idiom that, thanks to Britain's empire and to the economic might of monoglot Americans, has spread around the world. Should a language be the voice of a nation, strictly policing intrusions? Bernard Shaw advocated a "Pure English", which admitted exotic coinages only if their spelling was anglicised: timbre had to be naturalised as tamber. But one of the OED's promoters, Frederick Furnivall, was as welcoming to dialects and tribal neologisms as the Statue of Liberty in her summons to the huddled masses: "Fling our doors wide! All, all, not one, but all, must enter."

Don't be surprised that this sounds like the immigration policy of Gordon Brown's government. That's the point: lexicographers are language's border guards, at times permissive, in other periods suspicious and forbidding. Ogilvie, an Australian recruited by the dictionary team in Oxford to research foreign lendings, cleverly documents the discomfort of little England as it watched the language of Shakespeare and Milton turn into an indiscriminate Esperanto.

The 1928 OED couldn't bring itself to legitimise words such as aeroplane, African, appendicitis, cinema and jazz', although all were in current use. Radio and radium were likewise excluded. But, despite this wariness about scientific discovery and technical innovation, James Murray, the dictionary's first editor, was criticised for letting in words that weren't native and Ogilvie assails Robert Burchfield, the editor from 1957 to 1986, for attempting to close the door flung open by Furnivall. Her criticism of Burchfield has made her starchy treatise temporarily newsworthy, but I'm not persuaded that he impoverished our shared vocabulary by deleting words such as aberglaube, aposaturnium, calabazilla, danchi, juba and tacuacine.

Burchfield's account of what his critics gruesomely called "World Englishes"  how tone-deaf these curators of language are!  was condemned for neglecting the variants of English spoken in Nigeria, Kenya, Tanzania and Hong Kong, and for preferring to emphasise the speech of Britain's "former 'settler' colonies", such as Canada or Australia. The predilection was natural enough, since Burchfield was born in New Zealand. But this partiality condemned his work, attaching it to the world view of "an earlier era"  by which the hostile reviewer Ogilvie quotes meant the previous decade. Truth, in these cliquey circles, matters less than political correctness, and Burchfield's alleged crime was to have been insufficiently "post-colonial".

Ogilvie's own professional credentials include "a year living with an Australian Aboriginal community", where  while presumably eating witchetty grubs and fending off dingoes  she compiled "a grammar and dictionary of a previously undocumented Aboriginal language"; she doesn't say whether that language has yet produced its Shakespeare or Milton. Arriving in Oxford, she found herself patronised as an interloper from the Outback, like one of the loan words she studied. "Oh," said her boss when she introduced herself, "you're Australian." She had to stop herself saying: "G'day" and couldn't take her shoes off in the office. It further rankled that the tweedy fogeys with whom she consorted at meetings of the Philological Society "never looked at me" but concentrated on her "young male friend", who despite his other appealing qualities "knew absolutely nothing about the topic".

Dr Johnson, the most famous of dictionary-makers, wryly defined the lexicographer as a "harmless drudge". But Ogilvie is a drudge with a grudge. She likes the English language and the dictionary that is its monument; it's just the English themselves that she can't abide.