“Locution” and Etymologically Related Terms About Speech
Locution, meaning “style of speech” (in the sense of the art of speaking), stems from the Latin word loqui, meaning “to speak.” Here are the other words in English based on the Latin term, and their meanings.
A colloquy (literally, “speaking together”) is a conversation or a conference; the related term colloquium refers to a formal meeting consisting of one or more addresses by experts followed by a question-and-answer session. Interestingly, the adjective form colloquial has the antonymic senses of “informal” and “conversational.”
Words with the same root form include soliloquy (literally, “speaking alone”), the word for a monologue in a play in which a character shares his or her thoughts, as well as obloquy, which can mean “harsh criticism” or can refer to the condition of being criticized or discredited.
Meanwhile, ventriloquy, a variation of ventriloquism (literally, “speaking from the stomach”), denotes the practice of deceiving an audience for entertainment by speaking in such a way that the audience believes the voice is coming from another source, usually a puppet manipulated by the ventriloquist to appear to be talking. (A more obscure meaning is “expressing oneself through another,” especially as a writer does by having a fictional character represent his or her attitudes or beliefs.)
Grandiloquence (literally, “large speaking”) is a familiar term for a bombastic or pompous form of speaking, but a less well-known synonym is magniloquence (literally, “great speaking”), and vaniloquence (literally, “vain speaking”), which refers to foolish talk, is related in both formation and meaning. Somniloquence (literally, “sleep talking”), however, is a neutral word meaning “talking in one’s sleep.”
The difference between the meanings of eloquence and loquacity is a distinction between quality and quantity; an eloquent speaker is an effective one, but a loquacious one is merely talkative. Interlocutor might be perceived as meaning “one who interrupts,” but it simply (and neutrally) refers to a fellow participant in a conversation (interlocution literally means “speaking between”). However, circumlocution (which literally means “speaking around”) connotes a judgment: a circumlocutory person speaks evasively or verbosely.