Explorer
The Modal-Verb Shift
Watch shall die and should rise over the long eighteenth century.
English modal verbs (shall, will, may, might, must, ought, can, could, would, should) carry the load of expressing obligation, prediction, possibility, and politeness in any English sentence. The system shifted substantially between Shakespeare’s English and modern English. Shall retreated from being the dominant future modal to being a formal-register outlier. Ought retreated almost completely. Will and should expanded to fill the resulting space.
The Founders’ sixty-year writing window catches this shift in motion. The chart below plots each modal’s per-million rate across the Founders’ careers (binned by decade) with Shakespeare’s rate as a fixed dashed reference. Pick a modal above and watch the lines move.
Pick a modal verb
Shakespeare uses shall at 4014 occurrences per million words. The dashed horizontal line on the chart is that reference rate.
What to look for
The diachronic story is in the slope.
Shakespeare uses shall at 4,014 per million words. Every Founder bucket in the data sits well below that — the Founders are already on the far side of the shift. Adams’s shall rate runs 2,276/M in his pre-1780 writing, climbs modestly to 2,778/M in the 1780s, then declines to 1,798/M by the 1810s. Jefferson’s rate stays roughly flat around 2,500–3,300/M across his career. Washington and Hamilton stay near 2,000– 2,600/M; Madison drops further (1,183–1,477/M from the 1800s onward). The pattern across the six isn’t a sharp diachronic plunge but a steady gap from Shakespeare, with a softer downward drift within most Founders’ later careers. The eighteenth-century English modal system was no longer Shakespeare’s.
Will tells the complementary story. Founders use it at 4,500–8,800/M — at or above Shakespeare’s 5,562/M from the 1780s onward. The future tense has already moved from shall to will by the time these writers reach maturity.
The most striking gap is ought. Shakespeare uses it at 22 per million words: effectively zero. Every Founder uses it at five to fifty times Shakespeare’s rate — Madison highest at 1,035/M in the 1790s, Jefferson lowest at 111/M in the 1780s but climbing. Ought is the eighteenth-century’s moral modal: it expresses the obligation that follows from natural law or social duty. The Founders’ political writing reaches for it constantly. Shakespeare’s dramatic writing barely needs it. By the twenty-first century English has shed ought almost as completely as Shakespeare did.
Franklin is the only Founder whose corpus runs out before the 1790s, so his trajectory is short. Within that window his shall rate is normal-Founder (2,355/M pre-1780, 1,904/M in the 1780s), and his ought rate is the lowest of the six (313/M, 208/M). On the modal system, at least, Franklin doesn’t track Shakespeare closely — his absorbed-mode signature lives in archaic-form survival and vocabulary, not in modal choice.
Cross-reference with the Archaic Threshold (where modals appear at the boundary of the archaic vocabulary), or the Function-Word Fingerprint.