Remark on distinctive vocal sound (4)
I believe the answer is:
note
I believe this clue is a double definition.
'remark' is the first definition.
('note' can be a synonym of 'remark')
'distinctive vocal sound' is the second definition.
(eg a note of hesitation in one's voice)
'on' is the link.
(Other definitions for note that I've seen before include "Single tone; short letter" , "Short written message" , "Brief letter - distinction" , "Observe - musical symbol" , "Tone of a short record" .)