I am looking for an adjective/noun for someone who is able to speak/ makes speeches very well and uses words effectively to influence/impress people.
I believe the word you're looking for is "persuasive". This is an adjective. Someone who is able to speak (not speech, "speech" is the noun) very well and uses words effectively to influence people could be said to be persuasive.
A colloquial adjective: silver-tongued. "That silver-tongued con man convinced the entire city that they needed a monorail."
An eloquent speaker, orator, rhetorician ...
...describes perfectly the first part of your request but falls slightly short of 'influence' part.
So, to state your goal another way "a public speaker who communicates well and influences hearers".
Additionally, from followup comments, you desire not to imply persuasive toward the sense of having guile - a persuasion with trickery. (Perhaps the worst example of an articulate, influential speaker with guile being a propagandist.)
How about 'winsome orator'? (I don't think winsome alone will do. )
Some may oppose winsome on grounds of its popular definition of... "Charming, often in a childlike or naive way." But childlike fits especially, because it implies innocence and lack of guile.
Furthermore, Among the synonyms for winsome are fair, engaging, amiable. Perhaps I am just picking the synonyms I like.
The American Heritage Dictionary defn. of winsome notes...
"...the Indo-European root *wen-, meaning "to desire, strive for..." ... "... the verb win itself is from this root; its meaning is an extension of the sense "to strive for," namely, "to strive for with success, be victorious." ..."
So a winsome orator describes one who energetically and convincingly communicates.
To some extent, demagogue might also apply.
What about orator? It seems to me that persuasion is the essence of oratory.
protected by tchrist♦ Jun 28 '14 at 5:56
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