Many common words contain a doubled letter, for example LEER, GRAMMAR and DAZZLE. To find dictionary examples for every letter of the alphabet is a difficult but not impossible task. Well-known words can be found for 22 of the letters; the list below (supplied by the editor) gives the most commonly-encountered word in the Kucera and Francis million-word corpus.
"Consecutive Identical Letters,"
Word Ways: Vol. 14
, Article 8.
Available at: http://digitalcommons.butler.edu/wordways/vol14/iss3/8