In 20th International Unicode Conference, Washington, DC, USA, January 2002. [Postscript file, 46 kB] [PDF file, 133 kB]
Abstract: SITMO is a new input technique for accented and special letters of the Latin alphabet (or other alphabets of comparable size), which combines in a uniform way short key sequences for frequently used characters with an easily memorizable scheme to enter rarely used characters. Compared with traditional modifier techniques, SITMO requires less additional keys and allows to access more characters, while for most European languages, the average number of keystrokes per derived letter is similar (that is, close to 2).
Supplementary material: Letter frequency tables and sample replacement schemes [Unicode/UTF-8] [hexadeximal notation]