Identify Crown Dependency’s dialect (5)
I believe the answer is:
'dialect' is the definition.
(I know that dialect can be written as idiom)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for idiom that I've seen before include "Peculiarity of phrase in a language" , "Expression that does not make literal sense" , "Use of words" , "Vocabulary characteristic of a specific group" , "Dialect, vernacular" .)