Glen leaves parting message, in a manner of speaking (7)

I believe the answer is:

diction

I'm a little stuck... Click here to teach me more about this clue!

'manner of speaking' is the definition.
(a person's way of speaking)

I don't understand the rest of the clue.

(Other definitions for diction that I've seen before include "words for speech" , "Mode of speech" , "Style of enunciation" , "One's manner of speaking or pronouncing words" , "Manner of enunciation" .)

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app