Be sure to turn round Monsieur's tongue (7)
I believe the answer is:
burmese
'tongue' is the definition.
(Burmese is an example)
'be sure to turn round monsieur's' is the wordplay.
'to turn' indicates an anagram.
'round' means one lot of letters goes inside another.
'monsieur' becomes 'm'.
'be'+'sure'='besure'
'besure' with letters rearranged gives 'burese'.
'burese' enclosing 'm' is 'BURMESE'.
(Other definitions for burmese that I've seen before include "Breed of cat" , "Native to Myanmar" , "Asians" .)