Mess making class speak (7)
I believe the answer is:
clutter
'mess' is the definition.
(clutter is mess or disorganisation)
'class speak' is the wordplay.
'class' becomes 'cl' (I've seen this in other clues).
'speak' becomes 'utter' (synonyms).
'cl'+'utter'='CLUTTER'
'making' acts as a link.
(Other definitions for clutter that I've seen before include "Untidy lot of objects in room" , "Untidy accumulation of objects" , "Disorderly heap" , "Untidy mess" , "Confused mess" .)