'unintentionally' originates from Latin, specifically the word 'intentio,' where 'in-' meant 'not' and 'tendere' meant 'to stretch.' 'Forgotten' originates from Old English, specifically the word 'forgietan,' where 'for-' meant 'away' and 'gietan' meant 'to grasp.'

'unintentionally' changed from the Latin word 'intentio' and eventually became the modern English word 'unintentionally.' 'Forgotten' changed from the Old English word 'forgietan' and eventually became the modern English word 'forgotten.'

Initially, 'unintentionally' meant 'without intention,' and this meaning has largely remained the same in modern usage. 'Forgotten' initially meant 'to lose grasp of,' and this meaning has evolved to 'not remembered.'