The French speak loudly and spend extravagantly (4,3)
I believe the answer is:
lash out
'spend extravagantly' is the definition.
(I've seen this before)
'the french speak loudly' is the wordplay.
'the french' becomes 'la'.
'speak loudly' becomes 'shout' ('shout' can be a synonym of 'speak loudly').
'la'+'shout'='LASH OUT'
'and' is the link.
(Other definitions for lash out that I've seen before include "Vigorously attack" , "Strike (or spend) wildly" , "Punch wildly" , "React violently" , "unprovoked attack" .)