These were painstaking procedures. Markov counted vowels and consonants in a Russian novel to make probability rules for which letter would appear next. 30 years later, Shannon took the idea a step further by creating statistical models of language and generating text according to the rules he devised. Shannon’s first output was “OCRO HLI RGWR,” but his model did get a bit better.

https://spectrum.ieee.org/tech-talk/robotics/artificial-intelligence/andrey-markov-and-claude-shannon-built-the-first-language-generation-models