I am often asked whether it is true that English (vocabulary) is the richest in the world. After all, English has words that do not have good counterparts in other languages, right? Say, there's no appropriate Russian translation for the English privacy, badge or weekend. And isn't that the reason that so many words of English penetrate other languages with sometimes frightening speed?
Not quite so. First of all, for any English word difficult to translate into a given language, there are words in that language that are difficult to translate into English. What would, for example, be a good translation of the Hebrew word hutzpa or the Russian word dusha? One can easily come up with many other examples, and translators struggle with them on a daily basis.
However, one cannot draw any useful conclusions based solely on such examples. Nor can one provide an adequate measure of vocabulary richness of English (or any other language, for that matter) simply by looking at the word counts in a dictionary. For example, the Oxford English Dictionary (2nd edition) boasts over 600,000 definitions, while the Webster's Third New International Dictionary, Unabridged contains 475,000 main headwords. According to the Global Language Monitor's announcement, the English language had crossed the 1,000,000-word threshold on June 10, 2009 (that very day?!).
But according to the Oxford English Dictionary's own admission,
"How many words are there in the English language? There is no single sensible answer to this question. It's impossible to count the number of words in a language, because it's so hard to decide what actually counts as a word."
For reasons for this difficulty are many. There is no academy to define officially accepted words and spellings of English. New words are coined and borrowed regularly, with estimates reaching as high as 25,000 words per year. Archaic, dialectal, and regional words might or might not be widely considered as "English".
And old words fall out of usage or change their meaning, pronunciation and use.
Moreover, when comparing English word counts with those of other languages, problems are further compounded by morphological and orthographic differences across languages: what is considered a word in Yupik or Mohawk may be considered a whole sentence in English!
Thus, it is best to conclude the relatively large size of an average English language dictionary is evidence not of the "richer vocabulary" but of better lexicography. Or in some cases, different lexicographic principles, underlying the creation of English dictionaries. For example, if we compare English dictionaries with Russian ones, one major difference becomes apparent: in order to get into an English dictionary, a word or expression must simply exist and be used with high enough frequency. In contrast, a Russian word or expression must pass certain normativity tests in order to be recorded by most Russian dictionaries.
A word in a Russian dictionary bears a certain "stamp of approval", but not so for a word in an English dictionary. Thus, recent editions of English dictionaries routinely include such items as LOL and IMHO, while their Russian counterparts (ржунимагу and имхо, respectively) are not recorded by Russian dictionaries. (As a curious aside, the spell-checker used by this blog catches LOL but not IMHO as a misspelled word!)
A recent decision of the Great Academic Dictionary of Russian to include words блогер 'blogger' and гламурный 'glamorous' -- both obviously recent borrowings from English -- has been met with public indignation. The committee behind the dictionary argues that including such words in a dictionary can help normalize their spelling and pronunciation (for example, should блогер 'blogger' be spelled with two letters г or one? English spelling suggests using two, but Russian orthography would lean towards one). Yet, many Russians still feel that "in speech you can say anything you like, but a dictionary should only list proper words" (this quote is translated from a BBC Russian article on this issue).
So naturally, given their more inclusive nature English language dictionaries end up with more entries. But even if it were true that English vocabulary somehow contained more words than those of other languages, what would it matter? After all, in the words of Geoffrey Pullum:
"Precision, richness, and eloquence don't spring from dictionary page count. They're a function not of how well you've been endowed by lexicographical history but of how well you use what you've got. People don't seem to understand that vocabulary-size counting is to language as penis-length measurement is to sexiness."