'suddenly' originates from Middle English, specifically the word 'sodein,' where 'sodein' meant 'unexpected.' 'Disturbed' originates from Latin, specifically the word 'disturbare,' where 'dis-' meant 'apart' and 'turbare' meant 'to throw into disorder.'

'sodein' transformed into the modern English word 'sudden,' and 'disturbare' transformed into the modern English word 'disturb' through Old French 'destourber.'

Initially, 'sudden' meant 'unexpected,' and 'disturb' meant 'to throw into disorder,' which has largely remained the same in modern usage.