Back in Belfast with a north German accent (5)
I believe the answer is:
twang
'accent' is the definition.
(I've seen this before)
'back in belfast with a north german' is the wordplay.
'back in' says to take the final letters (the 'back' of the word).
'with' becomes 'w' (abbreviation).
'north' becomes 'N' (abbreviation).
'german' becomes 'g' (abbreviation).
The last letter of 'belfast' is 't'.
't'+'w'+'a'+'n'+'g'='TWANG'
(Other definitions for twang that I've seen before include "brogue" , "heard when listening to The Archers?" , "Sort of sound" , "Plucked string sound; nasal voice" , "Sound of a tense wire or bowstring being plucked" .)