Breathe in and talk softly (4)
I believe the answer is:
gasp
'breathe in' is the definition.
(thesaurus)
'talk softly' is the wordplay.
'talk' becomes 'gas' (I've seen this before).
'softly' becomes 'p'.
'gas'+'p'='GASP'
'and' acts as a link.
(Other definitions for gasp that I've seen before include "Short sharp intake of breath" , "Short laboured intake of breath" , "Catch one's breath in astonishment" , "Utter breathlessly" , "Say "ah"" .)