Four letters, nine sounds: English's most inconsistent spelling

The letter combination 'ough' can be pronounced at least nine different ways in English — compare through, though, thought, tough, cough, plough, thorough, hiccough and lough. It's a fossil of medieval pronunciation: the spelling froze centuries ago while the actual sounds kept drifting apart across dialects and words. A well-known pangram — 'a rough-coated, dough-faced ploughman coughed and hiccoughed' — crams in nearly all nine.

— Wikipedia contributors, Ough (orthography) — English orthography