Quick to speak (7)
I believe the answer is:
express
I believe this clue is a double definition.
'quick' is the first definition.
(I've seen this before)
'speak' is the second definition.
(I've seen this before)
'to' is the link.
(Other definitions for express that I've seen before include "Explicit" , "Squeeze out - speak" , "This train doesn't stop" , "Of train, travelling rapidly with few or no stops" , "Non-stop(ping)" .)