Speaker who starts as he finishes! (6)

I believe the answer is:

orator

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'speaker' is the definition.
(I know that orator is a type of speaker)

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for orator that I've seen before include "Rhetorician" , "Eloquent type" , "One who holds forth" , "A fluent public speaker" , "I declaim" .)

I've seen this clue in the Evening Standard.

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