Tongue-tied single, taciturn with ale drunk (12)
I believe the answer is:
inarticulate
'tongue-tied' is the definition.
('inarticulate' can be similar in meaning to 'tongue-tied')
'single taciturn with ale drunk' is the wordplay.
'single' becomes 'i' (one).
'with' means one lot of letters go next to another.
'drunk' is an anagram indicator.
'taciturn' after 'ale' is 'aletaciturn'.
'aletaciturn' is an anagram of 'narticulate'.
'i'+'narticulate'='INARTICULATE'
(Other definitions for inarticulate that I've seen before include "Unable to speak clearly" , "Tongue-tied" , "Unable to express oneself clearly" , "Not able to speak coherently" , "Unintelligible" .)