Code and ciphers: Julius Caesar, the Enigma and the internet

Table 2.6
From Julius Caesar to simple substitution 25
English French German Italian Welsh
A 57 72 49 103 77
B 9 13 18 4 13
C 17 17 28 46 23
D 26 34 43 42 63
E 116 143 129 95 55
F 28 7 11 8 28
G 14 11 20 12 32
H 46 9 42 11 43
I 58 56 69 103 57
J 1 1 1 0 0
K 5 0 8 0 0
L 34 42 25 58 47
M 14 35 36 20 23
N 57 54 58 58 58
O 53 48 24 69 64
P 18 27 7 16 3
Q 3 5 0 3 0
R 49 51 69 55 52
S 55 64 54 38 20
T 91 64 64 52 31
U 25 42 28 21 17
V 9 10 8 14 0
W 11 0 12 0 31
X 1 3 0 0 0
Y 18 3 0 0 67
Z 1 1 11 7 0
Other 184 188 186 165 196
A statistical analysis of these counts shows that English, French and
German and, to a lesser extent, Italian, are very closely related in so far as
single letter frequencies are concerned, whereas their relationship with
Welsh is noticeably weaker. A partial explanation is that Y is very
common in Welsh, being a vowel (with two different pronunciations), but
much less common in English and quite rare in the other languages. The
counts also show that N might be said to be ‘the most consistent letter’
since it occurs with virtually the same frequency in all five languages,
accounting for about 6% to 7% of all alphabetic text. For an explanation of
the statistical tests typically employed in comparing counts such as these
see [2.4]; for further comments see M20.