It was a successful publicity ploy by an American company that makes money by monitoring new media for mentions of its clients.
A million words were reached long ago, according to David Crystal, a very reliable linguistician. Exactly when depends on how you count ‘em.
The Oxford English Dictionary defines 6,15,100 words and illustrates their usage with 24,36,600 quotations. Of these words, 41,700 are obsolete, so you won’t be using them very often. There are even 240 ghost words — words that have never existed outside dictionaries.
The OED distinguishes 430 senses for the verb set. Is each a separate word? The OED does not include slang words or technical jargon, both categories being prolific generators of new (and often ephemeral) words.
It is certain, though, that English (because of its economic, political and cultural connections) has produced more words than any other language.
By 1066, English contained some 50,000 words. That is about the number that a well-educated speaker of English uses today.
In the High Middle Ages the number of words available grew to about 1,00,000 (with the introduction of French and Latin synonyms and abstract terms). In the age of Shakespeare the lexicon had swollen to about 2,00,000.
People overestimate how many words Shakespeare himself introduced into English. They often think he invented every word of which the dictionary shows him to have been the first user. But he is quoted so much because his works have been carefully studied, and because his printed plays exist, while many playwrights’ works have been lost.
The number of different words that he uses is about 20,000. (Professor Crystal points out that the First Folio contains these forms of the word take: take, takes, taketh, taking, tak’n, taken, tak’st, tak’t, took, took’st, tooke, tookst. Yet we naturally count them as one word.)
The number of words in Shakespeare’s day doubled after the Industrial Revolution. The growth of science made English vocabulary simply uncountable. Chapman and Hall’s chemical dictionaries include half a million compounds.
A chemist could work out what many of these compound names mean. That is one of the characteristics of vocabulary — that passive vocabulary outstrips active vocabulary; that is to say, we recognise more words than we use.
If you spent a year with a word-recognition computer you might get a fairly accurate idea of your general active vocabulary. If, after a while, you changed your company from that of musicians to that of patent agents, you’d chalk up thousands more words.
Anyone with 50,000 words available for use, with another 12,000 understood, is doing pretty well.
I’d say that there are easily a million words in English that you do not know. And nor do I.