Berth must be found in ship for people from neighbouring island (5)
I believe the answer is:
scots
'people from neighbouring island' is the definition.
The definition and answer can be both people as well as being plural nouns.
Perhaps there's an association between them I don't understand?
'berth must be found in ship' is the wordplay.
'berth' becomes 'cot' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'must be found in' indicates putting letters inside.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'cot' put within 'ss' is 'SCOTS'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for scots that I've seen before include "Taxes" , "eg Glaswegians" , "North British" , "Language of Burns" , "- Greys, - pine" .)