I spot a tricky dialect (6)
I believe the answer is:
patois
'dialect' is the definition.
(I know that patois is a type of dialect)
'i spot a tricky' is the wordplay.
'tricky' indicates anagramming the letters.
'i'+'spot'+'a'='ispota'
'ispota' anagrammed gives 'PATOIS'.
(Other definitions for patois that I've seen before include "manner of speaking" , "Regional (French) dialect" , "'Argot, vernacular (6)'" , "Language of group" , "Dialect or non-standard language" .)