'frequently' originates from Latin, specifically the word 'frequentia,' meaning 'a crowd or multitude.' 'Altered' comes from Latin 'alterare,' meaning 'to change.'

'frequentia' transformed into the Old French 'frequent,' and eventually became the modern English word 'frequent.' 'Alterare' became the Old French 'alterer,' and eventually the modern English 'alter.'

Initially, 'frequent' meant 'crowded' or 'numerous,' but over time it evolved to mean 'often occurring.' 'Alter' originally meant 'to change,' which remains largely the same today.