The frequency of the most common letter bigrams in a small English corpus is:[4]
th 1.52 en 0.55 ng 0.18
he 1.28 ed 0.53 of 0.16
in 0.94 to 0.52 al 0.09
er 0.94 it 0.50 de 0.09
an 0.82 ou 0.50 se 0.08
re 0.68 ea 0.47 le 0.08
nd 0.63 hi 0.46 sa 0.06
at 0.59 is 0.46 si 0.05
on 0.57 or 0.43 ar 0.04
nt 0.56 ti 0.34 ve 0.04
ha 0.56 as 0.33 ra 0.04
es 0.56 te 0.27 ld 0.02