Probability Of Occurrence of 26 Letters Letter Probability Letter Probability A .082 N .067 B .015 O .075 C .028 P .019 D .043 Q .001 E .127 R .060 F .022 S .063 G .020 T .091 H .061 U .028 I .070 V .010 J .002 W .023 K .008 X .001 L .040 Y .020 M .024 Z .001 The most frequent English digraphs per 200 letters are: TH--50 AT--25 ST--20 ER--40 EN--25 IO--18 ON--39 ES--25 LE--18 AN--38 OF--25 IS--17 RE--36 OR--25 OU--17 HE--33 NT--24 AR--16 IN--31 EA--22 AS--16 ED--30 TI--22 DE--16 ND--30 TO--22 RT--16 HA--26 IT--20 VE--16 The most frequent English trigraphs per 200 letters are: THE--89 TIO--33 EDT--27 AND--54 FOR--33 TIS--25 THA--47 NDE--31 OFT--23 ENT--39 HAS--28 STH--21 ION--36 NCE--27 MEN--20 Frequency of Initial and Final Letters: Letters- A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Initial- 9 6 6 5 2 4 2 3 3 1 1 2 4 2 10 2 - 4 5 17 2 - 7 - 3 - Final - 1 - 1017 6 4 2 - - 1 6 1 9 4 1 - 8 9 11 1 - 1 - 8 - Relative Frequencies of Vowels: A 19.5% E 32.0% I 16.7% O 20.2% U 8.0% Y 3.6% Average number of vowels per 20 letters, 8. Groups: 1. E, having a probability of about 0.127 2. T, A, O, I, N, S, H, R, each having probabilities between 0.06 - 0.09 3. D, L, having probabilities around 0.04 4. C, U, M, W, F, G, Y, P, B, each having probabilities between 0.015 - 0.023. 5. V, K, J, X, Q, Z, each having probabilities less.01.