Think aloud (4)
'think' is the definition.
(thesaurus)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for say that I've seen before include "Express in words" , "State; for instance" , "Articulate" , "Utter; for example" , "Verbalise" .)
(Other definitions for muse that I've seen before include "Ponder, say meditatively" , "Inspiring goddess" , "Cogitate" , "Contemplate -- a goddess of the liberal arts" , "Inspiration for poet etc - ponder" .)