Where does “locution” come from?

Locution comes from Latin locutio, derived from the Latin verb loquor meaning to speak, ultimately from Proto-Indo-European telkʷ-.

locution (English): A phrase or expression connected to an individual...

Definitions

Step	Language	Word	Meaning
1	Latin	locūtiō	—
2	Latin	loquor	I say, speak, tell, talk; I declare, utter
3	Proto-Italic	tlokʷōr	—
4	Proto-Indo-European	telkʷ-	to talk

locution — Etymology, Origin & Word History | Etymology Explorer