The question of the size of Shakespeare’s vocabulary has fascinated scholars for centuries. To answer that question, all scholars turn to The Harvard Concordance to Shakespeare by Martin Spevack (1968, 1974) based on the Riverside Shakespeare (G. Blakemore Evans, 1973). The concordance lists every word used in the published work of the Bard — a grand total of 884,647 words. Spevack also machine-counted 31,654 different words in 1968 and revised that to 29,066 different words in 1974. Using those numbers, different experts use different approaches to estimate the number or words that Shakespeare knew.
According to lexicographer and Shakespeare scholar David Crystal, the entire English vocabulary in the Elizabethan period consisted of about 150,000 words. Turning to the Harvard Concordance, Crystal notes that although Spevack machine-counted 29,066 unique words, that includes variant forms of words (eg, take, takes, taking, took, taken, takest) that are counted as different words. By removing those grammatical variants, the total of different words is reduced to 17,000 to 20,000. Therefore, Crystal believes that Shakespeare had a vocabulary of about 20,000 words (13.5% of the known lexicon). Compare that to the size of the vocabulary of the average modern person (high school-level education) that is 30,000 to 40,000 words (about 6% of the 600,000 words defined in the Oxford English Dictionary). Other lexicographers estimate that Shakespeare’s vocabulary ranged from 18,000 to 25,000 words.
In their 1976 study, “Estimating the Number of Unseen Species: How Many Words Did Shakespeare Know,” statisticians Bradley Efron (Stanford University) and Ronald Thisted (University of Chicago) used word-frequency analyses to predict more accurately Shakespeare’s actual vocabulary, including the words he used in his writing (active or manifest vocabulary) and the words he knew but didn’t use in his writing (passive or latent vocabulary). Efron and Thisted turned to the Harvard Concordance and the 31,654 different words from a grand total of 884,647 words, including repetitions. Of these words, 14,376 are used once, 4,343 are used twice, 2,292 are used three times, 1,463 are used four times, 1,043 are used five times, 837 are used six times, 638 are used seven times, 519 are used eight times, 430 are used nine times, and 364 are used ten times. These numbers are then plugged into a complicated formula — too labyrinthine to state here — that calculates how many new words would appear if new samples of Shakespeare’s works were discovered that were of similar length to ones already known. When Efron and Thisted repeated this calculation over and over, they arrived at an estimate of about 35,000 words that Shakespeare knew but did not use in his writings. Thus to calculate Shakespeare’s total working vocabulary, we add 31,534 different words found in his writings to the 35,000 words he probably knew, to arrive at an estimate of 66,534 words. Quod erat demonstrandum; or to say it more eloquently, borrowing the words of the immortal Bard: “If this be error and upon me proved, I never writ, nor no man ever loved.”
Read related posts: How Long Does it Take to Read a Million Words?
How Many Words in the English Language?
How Many Words Does the Average Person Speak in a Lifetime?
How Many Books Does the Average American Read?
For further reading: The Riverside Shakespeare (2nd Edition) by G. Blakemore Evans (1996)
The Harvard Concordance to Shakespeare by Marvin Spevack (1974)
“Estimating the number of unseen species: how many words did Shakespeare know?” by Brad Efron and Ronald Thisted, Biometrika 63:435-47 (1976)
100 Essential Things You Didn’t Know About Math and the Arts by John Barrow (2015)
The Shakespeare Miscellany by David Crystal and Ben Crystal (2005)
30 Great Myths About Shakespeare by Laurie Maguire and Emma Smith (2013)