Final answer:
Elocutionists like Thomas Sheridan believed in the power of effective public speaking, the teachability of eloquence, and the importance of gestures and vocal delivery in communication.
Step-by-step explanation:
Elocutionists like Thomas Sheridan believed all of the above, as they recognized the power of effective public speaking, the teachability of eloquence, and the importance of gestures and vocal delivery in communication. Sheridan and other elocutionists emphasized the significance of mastering these skills to engage and persuade audiences effectively.
The skilled use of language in rhetoric has been a part of educational curricula since ancient Greek times, where philosophers like Aristotle laid foundational work for public speaking protocols, influencing the likes of Sheridan and others in the practice of eloquence.