'predictably' originates from Latin, specifically the word 'praedicere,' where 'prae-' meant 'before' and 'dicere' meant 'to say.' 'Stay' originates from Old English, specifically the word 'stæg,' meaning 'to remain.'

'predictably' changed from the Latin word 'praedicibilis' and eventually became the modern English word 'predictably.' 'Stay' evolved from the Old English word 'stæg' to the modern English 'stay.'

Initially, 'predictably' meant 'able to be foretold,' and this meaning has largely remained the same in modern usage. 'Stay' initially meant 'to remain in place,' which is consistent with its current meaning.