Poor Italian curate leaves area, lacking fluency (12)
I believe the answer is:
inarticulate
'lacking fluency' is the definition.
(I've seen this before)
'poor italian curate leaves area' is the wordplay.
'poor' is an anagram indicator.
'leaves' is a deletion indicator.
'area' becomes 'a' (maths abbreviation).
'italian'+'curate'='italiancurate'
'italiancurate' with 'a' removed is 'itliancurate'.
'itliancurate' anagrammed gives 'INARTICULATE'.
(Other definitions for inarticulate that I've seen before include "Tongue-tied" , "Unintelligible" , "Unable to express oneself clearly" , "incapable of clear speech" , "Not able to speak coherently" .)