Bigram/Gram and Biphone/Phone frequencies for each language were calculated by dividing the sum of the log frequencies (obtained from subtitle corpora) of all of the words with element A at position N (or N & N+1 in the case of Bigrams/Biphones) by the sum of the log frequencies of all words with any character in position N (or N & N+1).

This method was obtained from:

Vitevitch, M.S. & Luce, P.A. (2004) A web-based interface to calculate phonotactic probability for words and nonwords in English. Behavior Research Methods, Instruments, and Computers, 36, 481-487.