Advanced Spelling Mistakes (C1) — Commonly Misspelled English Words

Even confident C1 writers slip on the same handful of words — accommodate, occurrence, conscientious, bureaucracy. This collection drills 25 of the most commonly misspelled advanced English words, chosen because the mistakes are genuinely hard to unlearn: silent letters (mnemonic, playwright), double consonants in the wrong place (embarrass, millennium, harass), French-origin traps (entrepreneur, liaison, questionnaire), and tricky endings like -ible vs -able.

Each word is paired with a precise definition and a natural example sentence at C1 register — academic, professional, editorial — so the spelling sticks in the contexts where you’ll actually need it: essays, reports, cover letters, research writing.

Looking for the general B1–B2 list first? Try our 50 most commonly misspelled English words. Otherwise, press play below and type your way through the C1 traps.