'slightly' originates from Old English, specifically the word 'sliht,' where 'sliht' meant 'smooth or even.' 'Changed' originates from Old French, specifically the word 'changier,' where 'changier' meant 'to alter or exchange.'

'slightly' changed from the Old English word 'sliht' and eventually became the modern English word 'slightly.' 'Changed' evolved from the Old French word 'changier' and became the modern English word 'changed' through Middle English.

Initially, 'slightly' meant 'smooth or even,' but over time it evolved into its current meaning of 'to a small degree.' 'Changed' initially meant 'to alter or exchange,' and this meaning has largely remained the same in modern usage.