The least used letter in the alphabet is Q

alphabet

The frequency of letters in text has often been studied for use in cryptography, and frequency analysis in particular. No exact letter frequency distribution underlies a given language, since all writers write slightly differently. Linotype machines sorted the letters’ frequencies as “E M F W Y P V B G K Q J X Z” based on the experience and custom of manual compositors. Likewise, Modern International Morse code encodes the most frequent letters with the shortest symbols; arranging the Morse alphabet into groups of letters that require equal amounts of time to transmit, and then sorting these groups in increasing order, yields “E I T S A N H U R D M W G V L F B K O P J X C Z Y Q”.