Articulate (adjective): able to express oneself clearly and effectively.
Vocabulary (noun): the stock of words used by a person or group.
Erudite (adjective): having or showing great knowledge or learning.
Profound (adjective): having great or intense meaning or importance.
Insightful (adjective): having or showing an ability to understand the deeper meaning or significance of something.
Persuasive (adjective): able to convince or influence someone to do or believe something.
Convincing (adjective): producing or tending to produce belief or conviction.
Rhetorical (adjective): relating to or characteristic of the art of effective or persuasive speaking or writing.
Oratory (noun): the art or practice of public speaking, especially in a formal and ceremonial manner.