English Spelling Statistics
Vivian Cook
Letter frequencies in English:
Single Letters Digrams Trigrams Letter position in word
Contact chart for English letters
Punctuation mark frequencies in English
Carney's Consonant Letter to Sound Correspondences in English
Most of these were intended for the Routledge Handbook of the English Writing System (2016) but were felt to be insufficiently rigorous for print. While they are rough and ready, they provide some information not otherwise available.