John Stuart Mill · 1806
Heavy going at CET-4 level. Not unreadable — just not readable the look-every-word-up way.
Coverage = the share of words in the text you already know. The research gives two lines: 98% before independent fluent reading is realistic, 95% for the instructional level that needs support (Hu & Nation, 2000). Proper nouns are not counted as unknown — recognising that it is a name is enough; this book has 244 of them.
Advanced — read it with glosses. 52,006 words in total; at 150 words a minute for a non-native reader, about 5 h 47 min to finish. Average sentence length 35.4 words — on the long side, so the load comes from sentence structure as much as from vocabulary. Reaching 95% coverage on this book (the floor for readability) takes roughly 18,500 word families.
The opening of On Liberty, word for word. Tap any word you don't know and its meaning here appears beside it — no sign-up, tap as often as you like.
John Stuart Mill was born on 20th May 1806. He was a delicate child, and the extraordinary education designed by his father was not calculated to develop and improve his physical powers. "I never was a boy," he says; "never played cricket." His exercise was taken in the form of walks with his father, during which the elder Mill lectured his son and examined him on his work. It is idle to speculate on the possible results of a different treatment. Mill remained delicate throughout his life, but was endowed with that intense mental energy which is so often combined with physical weakness. His youth was sacrificed to an idea; he was designed by his father to carry on his work; the individuality of the boy was unimportant. A visit to the south of France at the age of fourteen, in company with the family of General Sir Samuel Bentham, was not without its influence. It was a glimpse of another atmosphere, though the studious habits of his home life were maintained. Moreover, he derived from it his interest in foreign politics, which remained one of his characteristics to the end of his life. In 1823 he was appointed junior clerk in the Examiners' Office at the India House.
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Computed by Readii from the public-domain text (updated 2026-10-21), not estimated by hand. The Readii reading level is our own scale, anchored on unknown-word density; it is not the same system as Lexile or AR and does not convert directly. Unknown words are measured against the CET-4 ∪ Gaokao lists, so this is difficulty for a Chinese-speaking learner, not a native-child reading level.