European laboratory speak is complicated (9)
I believe the answer is:
elaborate
'is complicated' is the definition.
(I've seen this in another clue)
'european laboratory speak' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'laboratory' becomes 'lab' (synonyms).
'speak' becomes 'orate' (orating is a kind of speaking).
'e'+'lab'+'orate'='ELABORATE'
(Other definitions for elaborate that I've seen before include "Complicated - complex" , "involved" , "Complicated, with many parts or details" , "Very ornate or complex" , "Highly detailed" .)