I don't know how to answer the other parts of your comment, but your "double or even triple length" estimate might be off: From https://en.wikipedia.org/wiki/E

I don't know how to answer the other parts of your comment, but your "double or even triple length" estimate might be off: From https://en.wikipedia.org/wiki/Entropy_(information_theory) https://en.wikipedia.org/wiki/Entropy_(information_theory) > English text has between 0.6 and 1.3 bits of entropy for each character of message. For comparison if you used a random string of alphanumeric characters it will have lg(26 + 26 + 10) = 5.7 bits per character. So if your password is drawn from an english corpus, if the low end of the estimate is correct, it's only about as strong as a random password 9 times shorter (or 4 on the high end). But of course we don't want a grammatical english password. Question is how much entropy does our meat-based random generator actually lose due to language bias compared to random word selection from an english dictionary (which I don't disagree with the analysis of as long as it's machine generated).