How Are Dictionaries Made? Recording a Language That Will Not Hold Still

The central resource is a corpus, a very large collection of text and transcribed speech assembled to be representative of the language, running into billions of words and drawn from newspapers, fiction, academic writing, correspondence, broadcast and the web. Software then produces concordances, listing every occurrence of a word with its surrounding context, so that a lexicographer looking at a screen of several hundred real uses can see which senses exist, how common each is, what words habitually appear alongside it, which grammatical patterns it enters and whether it is formal, technical, regional or rude. Before computers this was done by hand on paper slips, and the Oxford English Dictionary's first edition was built from around five million such slips contributed by volunteer readers over decades, who were asked to copy out sentences illustrating words and post them in. That project's most prolific contributor, William Chester Minor, sent in thousands of quotations from a secure psychiatric hospital where he was detained after killing a man.

The parts of an entry each require a separate set of decisions:

• •The headword and its variant spellings, which requires deciding whether two forms are one word or two
• •Pronunciation, in a phonetic alphabet, and the choice of which accent to represent as the default is itself contested
• •Etymology, tracing the word back as far as the evidence supports and no further, with honest admissions of uncertainty where the trail stops
• •Sense division, which is the hardest part, since meaning is continuous and an entry must cut it into discrete numbered senses that no speaker actually has in their head
• •Order of senses, either historical, as in the Oxford dictionary, where the oldest meaning comes first, or by frequency, as in most learner dictionaries, and the two produce very different-looking entries
• •Citations showing the word in use, with the earliest known example dating its entry into the language
• •Labels for register, region, currency and offensiveness, each of which is a judgement that will be argued with

Samuel Johnson began his dictionary of 1755 intending to fix the language and concluded in his preface that the attempt was futile, comparing a lexicographer trying to arrest change to someone lashing the wind. The modern profession is descriptive by default, which regularly produces public anger, since a dictionary that records a disputed usage is accused of endorsing it. The clearest case is Webster's Third New International Dictionary of 1961, which dropped most usage labels, included words that critics considered illiterate, and defined ain't without condemnation; the reaction was ferocious, with reviewers accusing it of abandoning standards and one magazine calling it a scandal. The dictionary was right about how English was being used and it also demonstrated that readers want guidance as well as description, which is why many dictionaries since have added usage notes explaining that a form is disputed without refusing to list it.

The criteria for inclusion are evidential rather than aesthetic. A word needs sustained use over a period, typically several years, across a range of independent sources, in contexts where its meaning is not being explained, which shows that readers are expected to know it. That is why a word coined by a newspaper and repeated within one industry does not qualify, and why slang that survives a decade does. Words are rarely removed from the largest historical dictionaries, which aim to record everything the language has ever contained and mark obsolete terms as such, while smaller print dictionaries must cut to make room and have been criticised for dropping nature words in children's editions in favour of technology terms. The other direction is more active than ever, since the web supplies evidence in quantities that make it possible to track a word's spread within months of its appearance, and major dictionaries now publish updates quarterly rather than waiting for a new edition.

Historical dictionaries operate on timescales that are hard to credit. The Oxford English Dictionary was proposed in 1857, began publication in fascicles in 1884, and was completed in 1928, taking seventy years and outliving several editors including James Murray, who worked in a corrugated iron shed in his garden and died with the letters past T unfinished. Its second edition appeared in 1989, and a full revision begun in 1993 is still in progress, published online and expected to continue for many years. The Grimm brothers began a German dictionary in 1838 that was finished in 1961, by which time the early entries needed revising. A dictionary of ancient Egyptian begun in Berlin in 1897 has run for over a century, and a Sanskrit project in Pune since 1948. The lesson these projects illustrate is that a complete description of a living language is a moving target: by the time the last entry is written, the first is out of date, which is why the online form, continuously revised and never finished, suits the work better than a book ever did.

Once the senses are divided, each still has to be put into words, and lexicographers follow conventions that readers rarely notice. A traditional definition names a broader class and then says what sets this item apart within it, so a chair becomes a seat for one person, with a back. A good definition should also be substitutable: it ought to fit into a real sentence in place of the word without turning it into nonsense. Learner dictionaries go further and write every definition using a limited defining vocabulary of a couple of thousand common words, so that nobody has to look up the words used to explain another word.

Circularity is the trap that every dictionary fights. If big is defined as large and large as big, the reader has learned nothing, and the smallest function words, such as the, of and if, are among the hardest entries to write for this reason. Errors do slip through. The best-known is dord, which appeared in Webster's Second New International Dictionary in 1934 as a word meaning density; it began as a slip reading 'D or d', an abbreviation, which was misfiled as a word, and it stayed in print for years before an editor noticed that no citations stood behind it.

Not every false word in a dictionary is an accident. Reference publishers have long worried about rivals copying their work, which is hard to prove when the material is a list of facts that anyone could in principle gather. One defence is a deliberate fake entry: if it turns up in a competitor's book, it can only have been copied. The best-known dictionary example is esquivalience, defined as deliberately avoiding one's official duties, which was planted in the New Oxford American Dictionary in 2001. A journalist exposed it in 2005, and by then it had already been picked up by at least one dictionary website.

Such entries are sometimes called mountweazels, after Lillian Virginia Mountweazel, a fictitious photographer given a straight-faced biography in an American encyclopedia in 1975. Mapmakers use the same trick with invented streets and villages. Agloe, a made-up hamlet placed on a New York State road map in the 1930s, became famous when a general store was later built at the spot and named after it, briefly turning the fiction into a real place. For a lexicographer the trap has a cost, since a dictionary's value rests on trust, and readers who discover one invented entry may reasonably wonder what else has been made up.

Samuel Johnson's Dictionary of the English Language, published in 1755, was not the first English dictionary, but it was the most influential for more than a century. Working with only a handful of assistants over about nine years, Johnson defined some forty thousand words and illustrated them with quotations from English writers, setting a method later dictionaries followed.

He also allowed himself some personality. He defined a lexicographer as a writer of dictionaries, a harmless drudge, and oats as a grain which in England is generally given to horses, but in Scotland supports the people. Modern dictionaries avoid such opinions, but Johnson's work shows how much a dictionary once depended on the judgement and wit of a single editor.

Lexicographers work from a corpus of billions of words of real usage, reading concordances that show every occurrence in context, and they describe what words are being used to mean rather than granting permission. An entry requires decisions about variants, pronunciation, etymology, how to divide continuous meaning into discrete senses, and what to label as informal or offensive. Inclusion depends on sustained independent use over years, the descriptive approach caused a public scandal in 1961, and the great historical dictionaries take so long that their earliest entries need revising before the last are written.