Twangy start to accompaniment disturbing northern girl (5)
I believe the answer is:
nasal
'twangy' is the definition.
(I've seen this before)
'start to accompaniment disturbing northern girl' is the wordplay.
'start to' says to take the initial letters.
'disturbing' indicates putting letters inside (inserted letters disrupt or disturb the word).
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'girl' becomes 'sal' (feminine given name).
The first letter of 'accompaniment' is 'a'.
'n'+'sal'='nsal'
'a' going inside 'nsal' is 'NASAL'.
(Other definitions for nasal that I've seen before include "front piece of helmet" , "like the sound from an organ" , "description of Alain's vowels" , "Relating to one's hooter" , "Rhinal" .)