Johnson is the Economist newspaper's (magazine's) language blog (named after Dr Samuel Johnson). It is produced by a team of writers-linguists and deals with everyday language matters with great authority.
Johnson recently gave a good thrashing to Stephen Fry – and others – who like to boast that English language has the richest vocabulary in the world. If you heard such claims, or repeated them, or argued with your French friends about the subject, I suggest you read the Johnson take on the topic to have a clearer idea of what we are talking about:
STEPHEN FRY, whom I always enjoy, makes a claim (at about 6:10 of the video) [English] certainly has the largest vocabulary ... by a long, long, long long, way. Rather as China is to the rest of the world in population, English is in the population of its words. Is that true, a friend e-mails me to ask?
There's a longish answer. For the summary version, skip to the end. For the really short version, though, the answer is "Sorry, Mr Fry." English is certainly rich in vocabulary, but this claim is nearly always made by enthusiastic lovers of English who don't really know how the many varieties of language beyond English work. It's not that another language has more words. The comparison simply can't be made in any agreed apples-to-apples way.
For example:
Moreover, many languages habitually build long words from short ones. German is obvious. Are compounds new words? Given the possibilities for compounds, German would quickly outstrip English, with new legitimate German "words", which Germans would accept without blinking, coined every day. Just one quick glance at the Frankfurter Allgemeine Zeitung's home-page finds Abschiedsvorstellung ("leave-taking performance", about South Africa putting on a display for the departing French in the World Cup), Weltmarktführer ("world market leader"), Stromtarifrechner ("electricity bill calculator") and so on. There's no reason to say "it's incredible how the Germans have a word for 'leave-taking performance'," because to create such words ad hoc is banal in German. This is even truer for Turkish. So Turkish and German and a host of others like them have "more words" than English.
And, giving the summary, Johnson comes to us, Normans:
We could go on in this vein for quite a while, but that will do for now. If I had to give a short answer to the question "does English have the biggest vocabulary?," I'd say "Who cares?" English is a rich and beautiful language, not least because England has been conquered by Vikings and Normans, and has happily been open to foreign influence through its history. We know more of its wonderful rare words because English has been written for over a thousand years, and its many dialects are well described. That's good enough for me. We shouldn't need it to have the biggest vocabulary—which can't be defined in any sensible way—to enjoy it.
And here is Blackadder trying to rewrite Johnson's dictionary with the help of Baldrick:
And here is Blackadder trying to rewrite Johnson's dictionary with the help of Baldrick: