Letter frequencies
From Wikipedia, the free encyclopedia
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 etaoin shrdlu cmfwyp vbgkqj xz 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 it san hurdm wgvlfbk opjxcz yq. Similar ideas are used in modern data-compression techniques such as Huffman coding.
More recent analyses show that letter frequencies, like word frequencies, tend to vary, both by writer and by subject. One cannot write an essay about x-rays without using frequent Xs, and different authors have habits which can be reflected in their use of letters.
Everyone writes differently – for example, Hemingway's writing style is visibly different from Faulkner's. Letter, bigram, trigram, word frequencies, word length, and sentence length can be calculated for specific authors, and used to prove or disprove authorship of texts, even for authors whose styles aren't so divergent.
Accurate average letter frequencies can only be gleaned by analyzing a large amount of representative text. With the availability of modern computing and collections of large text corpora, such calculations are easily made.
Contents |
[edit] Relative frequencies of letters in the English language
| Letter | Frequency |
|---|---|
| a | 8.167% |
| b | 1.492% |
| c | 2.782% |
| d | 4.253% |
| e | 12.702% |
| f | 2.228% |
| g | 2.015% |
| h | 6.094% |
| i | 6.966% |
| j | 0.153% |
| k | 0.772% |
| l | 4.025% |
| m | 2.406% |
| n | 6.749% |
| o | 7.507% |
| p | 1.929% |
| q | 0.095% |
| r | 5.987% |
| s | 6.327% |
| t | 9.056% |
| u | 2.758% |
| v | 0.978% |
| w | 2.360% |
| x | 0.150% |
| y | 1.974% |
| z | 0.074% |
[edit] Relative frequencies of letters in other languages
| Letter | French [2] | German [3] | Spanish [4] | Esperanto [5] | Italian[6] | Turkish | Swedish[7] |
|---|---|---|---|---|---|---|---|
| a | 7.636% | 6.51% | 12.53% | 12.12% | 11.74% | 11.68% | 9.3% |
| b | 0.901% | 1.89% | 1.42% | 0.98% | 0.92% | 2.95% | 1.3% |
| c | 3.260% | 3.06% | 4.68% | 0.78% | 4.5% | 0.97% | 1.3% |
| d | 3.669% | 5.08% | 5.86% | 3.04% | 3.73% | 4.87% | 4.5% |
| e | 14.715% | 17.40% | 13.68% | 8.99% | 11.79% | 9.01% | 9.9% |
| f | 1.066% | 1.66% | 0.69% | 1.03% | 0.95% | 0.44% | 2.0% |
| g | 0.866% | 3.01% | 1.01% | 1.17% | 1.64% | 1.34% | 3.3% |
| h | 0.737% | 4.76% | 0.70% | 0.38% | 1.54% | 1.14% | 2.1% |
| i | 7.529% | 7.55% | 6.25% | 10.01% | 11.28% | 8.27%* | 5.1% |
| j | 0.545% | 0.27% | 0.44% | 3.50% | 0.00% | 0.01% | 0.7% |
| k | 0.049% | 1.21% | 0.00% | 4.16% | 0.00% | 4.71% | 3.2% |
| l | 5.456% | 3.44% | 4.97% | 6.14% | 6.51% | 5.75% | 5.2% |
| m | 2.968% | 2.53% | 3.15% | 2.99% | 2.51% | 3.74% | 3.5% |
| n | 7.095% | 9.78% | 6.71% | 7.96% | 6.88% | 7.23% | 8.8% |
| o | 5.378% | 2.51% | 8.68% | 8.78% | 9.83% | 2.45% | 4.1% |
| p | 3.021% | 0.79% | 2.51% | 2.74% | 3.05% | 0.79% | 1.7% |
| q | 1.362% | 0.02% | 0.88% | 0.00% | 0.51% | 0 | 0.007% |
| r | 6.553% | 7.00% | 6.87% | 5.91% | 6.37% | 6.95% | 8.3% |
| s | 7.948% | 7.27% | 7.98% | 6.09% | 4.98% | 2.95% | 6.3% |
| t | 7.244% | 6.15% | 4.63% | 5.27% | 5.62% | 3.09% | 8.7% |
| u | 6.311% | 4.35% | 3.93% | 3.18% | 3.01% | 3.43% | 1.8% |
| v | 1.628% | 0.67% | 0.90% | 1.90% | 2.10% | 0.98% | 2.4% |
| w | 0.114% | 1.89% | 0.02% | 0.00% | 0.00% | 0 | 0.03% |
| x | 0.387% | 0.03% | 0.22% | 0.00% | 0.00% | 0 | 0.1% |
| y | 0.308% | 0.04% | 0.90% | 0.00% | 0.00% | 3.37% | 0.6% |
| z | 0.136% | 1.13% | 0.52% | 0.50% | 0.49% | 1.50% | 0.02% |
| à | 0.486% | 0 | 0 | 0 | see a | 0 | 0.0% |
| å | 0 | 0 | 0 | 0 | 0 | 0 | 1.6% |
| ä | 0 | 0 | 0 | 0 | 0 | 0 | 2.1% |
| œ | 0.018% | 0 | 0 | 0 | 0 | 0 | 0 |
| ç | 0.085% | 0 | 0 | 0 | 0 | 1.26% | 0 |
| ĉ | 0 | 0 | 0 | 0.66% | 0 | 0 | 0 |
| è | 0.271% | 0 | 0 | 0 | see e | 0 | 0.0% |
| é | 1.904% | 0 | 0 | 0 | see e | 0 | 0.0% |
| ê | 0.225% | 0 | 0 | 0 | 0 | 0 | 0 |
| ë | 0.000% | 0 | 0 | 0 | 0 | 0 | 0 |
| ĝ | 0 | 0 | 0 | 0.69% | 0 | 0 | 0 |
| ğ | 0 | 0 | 0 | 0 | 0 | 1.13% | 0 |
| ĥ | 0 | 0 | 0 | 0.02% | 0 | 0 | 0 |
| î | 0.045% | 0 | 0 | 0 | 0 | 0 | 0 |
| ì | 0 | 0 | 0 | 0 | see i | 0 | 0 |
| ï | 0.005% | 0 | 0 | 0 | 0 | 0 | 0 |
| ı | 0 | 0 | 0 | 0 | 0 | 5.20%* | 0 |
| ĵ | 0 | 0 | 0 | 0.12% | 0 | 0 | 0 |
| ñ | 0 | 0 | 0.03 | 0 | 0 | 0 | 0 |
| ò | 0 | 0 | 0 | 0 | see o | 0 | 0 |
| ö | 0 | 0 | 0 | 0 | 0 | 0.87% | 1.5% |
| ŝ | 0 | 0 | 0 | 0.38% | 0 | 0 | 0 |
| ş | 0 | 0 | 0 | 0 | 0 | 1.94% | 0 |
| ß | 0 | 0.31% | 0 | 0 | 0 | 0 | 0 |
| ù | 0.058% | 0 | 0 | 0 | see u | 0 | 0 |
| ŭ | 0 | 0 | 0 | 0.52% | 0 | 0 | 0 |
| ü | 0 | 0 | 0 | 0 | 0 | 1.99% | 0 |
-*See Turkish dotted and dotless I
[edit] See also
- Corpus linguistics
- ETAOIN SHRDLU
- RSTLNE
- Frequency analysis (cryptanalysis)
- Linotype machine
- Most common words in English
- Scrabble
[edit] References
- ^ English letter frequencies
- ^ CorpusDeThomasTempé. Retrieved on 2007-06-15.
- ^ Albrecht Beutelspacher, Kryptologie, 7. Aufl., Wiesbaden: Vieweg Verlagsgesellschaft, 2005, ISBN 3-8348-0014-7, p.10
- ^ Fletcher Pratt, Secret and Urgent: the Story of Codes and Ciphers Blue Ribbon Books, 1939, pp. 254-255.
- ^ La Oftecoj de la Esperantaj Literoj. Retrieved on 2007-09-14.
- ^ Simon Singh, Codici e Segreti, 1999, RCS, ISBN 88-17-12539-3
- ^ Simon Singh, Kodboken, 1999, Norstedts, ISBN 91-1-1300708-4
