Emphasise dialect (6)
I believe the answer is:
accent
This clue is a double definition.
'emphasise' is the first definition.
(synonyms)
'dialect' is the second definition.
(synonyms)
(Other definitions for accent that I've seen before include "A diacritic mark" , "Regional speech characteristic" , "A localised way of speaking" , "Pronunciation in a locality" , "Stress - regional dialect" .)