... acute in writing, maybe. Alternatively, there’s one’s expression when talking ... (6)
I believe the answer is:
'acute' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for accent that I've seen before include "Local way of pronouncing words" , "Stress, emphasis" , "Local way of speaking or enunciation" , "A localised way of speaking" , "Regional speech characteristic" .)