Impudence before lecturer becomes an interpreter (9)

I believe the answer is:
lipreader
'an interpreter' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'impudence before lecturer' is the wordplay.
'impudence' becomes 'lip' (lip is a kind of impudence).
'before' says to put letters next to each other.
'lecturer' becomes 'reader' (synonyms).
'lip'+'reader'='LIPREADER'
'becomes' acts as a link.
Can you help me to learn more?
I've seen this clue in The Daily Express.
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