It's crucial to establish ring has been stolen, and get the last word in before talk is cut short (11)
I believe the answer is:
fundamental
'it's crucial' is the definition.
(thesaurus)
'ring has been stolen and get the last word in before talk is cut short' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'and' is 'nda' which is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within the answer.
'last' could be 'f' (I've seen this in other clues) and 'f' is present in the answer.
'before' could be 'e' (I've seen this in other clues) and 'e' is found in the answer.
This explanation may well be incorrect...
'to establish' is the link.
Can you help me to learn more?
(Other definitions for fundamental that I've seen before include "key" , "Basic" , "Primary" , "Of central importance" .)