When one character gives a talk to another that does or is meant to somehow break down the recipient or gain a psychological advantage over them by claiming uncomfortable things that they cannot deny.
Also known as a Breaking Speech or Breaking Lecture.note
This is often achieved by a kind of "The Reason You Suck" Speech, telling the other character how pathetic they are or perhaps how guilty of something terrible, perhaps a "Not So Different" Remark from someone unpalatable, but there are other ways of breaking someone down by talking. You could for example instead deconstruct the world, other characters, or their relationship with the victim. The important part is that they can't deny your words, at least not in the heat of the moment, and you gain a psychological advantage over them. Uncomfortable truths (or at least half-truths) and logical arguments are effective for making claims hard to deny, but hitting emotional weak spots is also important and can work even if your statements are not truly reasonable.
Results, when successful, range from the mere chance of getting to smirk in a satisfied way for rattling someone in an otherwise superior position; through distracting or demoralizing an opponent to make them easier to beat; to bringing about Break the Cutie, Heroic BSoD, Villainous Breakdown or even Face–Heel Turn, More than Mind Control, or Driven to Suicide. The most extreme form would be Mind Rape by just talking, but be wary of automatically calling every instance of Breaking Them by Talking that.
Obviously, this is easier to pull off from a relative position of power, such as when you have just defeated someone, or when interrogating a prisoner, but it goes both ways. It's even more impressive when someone manages to turn the tables on someone who was in a superior position. When this is done by one being interrogated — and only then — it's the Hannibal Lecture. Naturally, in between these cases, there is the one where both parties start out on an equal footing.
Note that a lot of this hinges on the victim actually caring about what you have to say, or otherwise respecting you enough to take your opinion seriously. If the victim is Too Dumb to Fool, or simply doesn't care about your opinion, then all you're likely to get for your trouble is laughter or a blank stare.
Some good tropes to use in the Breaking Speech include Brutal Honesty, Cowardice Callout, "Not So Different" Remark, Tomato in the Mirror, and They Died Because of You.
As stated above, there is frequent overlap with "The Reason You Suck" Speech, but the concepts are not the same. "The Reason You Suck" Speech is about what you say, this is about what you do by saying it. You can tell someone they suck without breaking them down or even intending to do so, particularly if you're just annoyed, and you can break someone down without telling them why they suck.
The distilled version of this is the Armor-Piercing Question. If the declarations used as a weapon come from simple clues, this is a form of Sherlock Scan. Some characters have the ability to do this as a superpower, which may be an example of Awesome by Analysis. Can be done as part of Evil Gloating. Shut Up, Hannibal! is a way of countering this trope. The opposite effect is done by a "No More Holding Back" Speech, when the hero tells about his own flaws and how they don't matter now. The reverse or "good counterpart" is the Kirk Summation or Talking the Monster to Death. Hannibal Lecture is a specific subtrope.
For examples of literally breaking someone by talking, see Weapons-Grade Vocabulary or Make Me Wanna Shout. Works using this trope may discuss The Power of Language.
See also: To the Pain, Talking Your Way Out, Just Between You and Me, And Then What?, Verbal Judo.
