Verbose in speech supporting tongue action (6)
I believe the answer is:
prolix
'verbose' is the definition.
(similar in meaning)
'speech supporting tongue action' is the wordplay.
I cannot really understand how this works, but
'supporting' could be 'pro' (being pro something is supporting it) and 'pro' is found within the answer.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for prolix that I've seen before include "Tediously wordy, talks too much" , "Wordy, long-winded" , "Tediously wordy and lengthy" , "Using many words" , "Tediously verbose" .)