How were the letter distribution and scores decided for the game?
When architect Alfred Mosher Butts was designing the game in the 1930s, studied the front page of The New York Times and did calculations of letter frequency. His basic cryptographic analysis of our language and his original tile distribution have remained valid. The letter ‘E’ is on the highest number of tiles—12. There is only one tile for each of the letters ‘J’, ‘K’, ‘Q’, ‘X’ and ‘Z’.
Butts assigned a point value to each letter according to its frequency of use. The letters with the highest point value are ‘Q’ and ‘Z’.