Files W.F.F. Archive Publications William Friedman's Copy of John C. Hartfield "Lisbonian" Selection of Roots and Terminals, Containing 21,323 Five Letter Words Equal to 454,670,329 Ten Letter Words, of A Clear, Euphonious and Pronounceable Character. with at Least 2 Letters Difference Between Each Group of 5 Letters, and Telegraphically Dissimilar by European and American Morse. Each Syllable of Which Is In Current Use and Can Be Verified by Dictionaries and the Official Vocabulary. In Strict Accordance with the Decision of the Lisbon Telegraph Conference, 1908, Governing the Use of Artificial Words. Compiled by John Charles Hartfield, 1911.