Researching a character for a script, I came across a Wikipedia article on Thought Disorder and was surprised to find how many of the symptoms actually show up in Tarantino’s scripts’ dialogue:

Thought is revealed through speech. Thus, observation of patterns of thought naturally involves close observation of the speech of the individual being considered. Although it is normal to exhibit some of the following, especially at times of stress, it is the degree and the resulting functional impairment that leads to the conclusion that the person being observed has a thought disorder.

Blocking – Interruption of train of speech before completion. e.g. “Am I early?”, “No, you’re just about on-” This is commonly seen when a joke is being told and the speaker forgets the punchline. At an extreme degree, after blocking occurs, the speaker does not recall the topic he or she was discussing.

Circumferential speech – Speech that is very delayed at reaching its goal. Speaking about many concepts related to the point of the conversation before eventually returning to the point and concluding the thought. Excessive long-windedness. e.g. “What is your name?” “Well, sometimes when people ask me that I have to think about whether or not I will answer because some people think it’s an odd name even though I don’t really because my mom gave it to me and I think my dad helped but it’s as good a name as any in my opinion but yeah it’s Tom.”

Clanging – Sounds, rather than meaningful relationships, appear to govern words or topics. Excessive rhyming. e.g. “I’m not trying to make noise. I’m trying to make sense. If you can’t make sense out of nonsense, well, have fun.” “I heard the bell. Well, hell, I heard the bell.”

Derailment (also Loose Association and Knight’s Move thinking) – Ideas slip off the topic’s track on to another which is obliquely related or unrelated. e.g. “The next day when I’d be going out you know, I took control, like uh, I put bleach on my hair in California.”

Distractible speech – During mid speech, the subject is changed in response to a stimulus. e.g. “Then I left San Francisco and moved to… where did you get that tie?”

Echolalia – Echoing of one’s or other people’s speech that may only be committed once, or may be continuous in repetition. This may involve repeating only the last few words or last word of the examiner’s sentences. This can be a symptom of Tourette’s Syndrome. e.g. “What would you like for dinner?”, “That’s a good question. That’s a good question. That’s a good question. That’s a good question.”

Evasive Interaction – Attempts to annunciate ideas and/or feelings about another individual comes out as evasive or in a diluted form. e.g. “I… er ah… you are uh… I think you have… uh– acceptable erm… uh… hair.”

Flight of Ideas – A sequence of loose associations or extreme tangentiality where the speaker goes quickly from one idea to another seemingly unrelated idea. To the listener, the ideas seem unrelated and do not seem to repeat. Often pressured speech is also present. e.g. “My hand is five cigars. I’ve been to Havana. She rose out of the water, bikini. Mushrooms clouds, Wow. You’re God.”

Illogicality – Conclusions are reached that do not follow logically (non-sequiturs or faulty inferences). e.g. “Do you think this will fit in the box?” draws a reply like “Well duh; it’s brown isn’t it?”

Incoherence (word salad) – Speech that is unintelligible because, though the individual words are real words, the manner in which they are strung together results in incoherent gibberish, e.g. the question “Why do people comb their hair?” elicits a response like “Because it makes a twirl in life, my box is broken help me blue elephant. Isn’t lettuce brave? I like electrons. Hello, beautiful.”

Loss of goal – Failure to show a train of thought to a natural conclusion. e.g. “Why does my computer keep crashing?”, “Well, you live in a stucco house, so the pair of scissors needs to be in another drawer.”

Neologisms – New word formations. These may also involve elisions of two words that are similar in meaning or in sound. e.g. “I got so angry I picked up a dish and threw it at the geshinker.”

Perseveration – Persistent repetition of words or ideas. e.g. “It’s great to be here in Nevada, Nevada, Nevada, Nevada, Nevada.” This may also involve repeatedly giving the same answer to different questions. e.g. “Is your name Mary? Yes. Are you in the hospital? Yes. Are you a table? Yes.”

Phonemic paraphasia – Mispronunciation; syllables out of sequence. e.g. “I slipped on the lice and broke my arm.”

Pressure of speech – An increase in the amount of spontaneous speech compared to what is considered customary. This may also include an increase in the rate of speech. Alternatively it may be difficult to interrupt the speaker; the speaker may continue speaking even when a direct question is asked.

Self-reference – Patient repeatedly and inappropriately refers back to self. e.g. “What’s the time?”, “It’s 7 o’clock. That’s my problem.”

Semantic paraphasia – Substitution of inappropriate word. e.g. “I slipped on the coat, on the ice I mean, and broke my book.”

Stilted speech – Speech excessively stilted and formal. e.g. “The attorney comported himself indecorously.”

Tangentiality – Replying to questions in an oblique, tangential or irrelevant manner. e.g:

Q: “What city are you from?”
A: “Well, that’s a hard question. I’m from Iowa. I really don’t know where my relatives came from, so I don’t know if I’m Irish or French.”

Word approximations – Old words used in a new and unconventional way. e.g. “His boss was a seeover.”