Articulate part of speech on engineer (9)
I believe the answer is:
pronounce
'articulate' is the definition.
('pronounce' can be a synonym of 'articulate')
'part of speech on engineer' is the wordplay.
'part of speech' becomes 'pronoun' (I've seen this before).
'on' says to put letters next to each other.
'engineer' becomes 'ce'.
'pronoun'+'ce'='PRONOUNCE'
(Other definitions for pronounce that I've seen before include "Articulate - judge" , "Declare, announce" , "Articulate in a certain way" , "make a declaration" , "say" .)