Stress, emphasis (6)
I believe the answer is:
accent
I believe this clue is a double definition.
'stress' is the first definition.
(accent can mean to emphasise or stress)
'emphasis' is the second definition.
(synonyms)
(Other definitions for accent that I've seen before include "Local way of pronouncing words" , "Stress - regional dialect" , "Local way of speaking or enunciation" , "A localised way of speaking" , "Emphasis; mark on a letter" .)