I am pretty good at reciting Peter Piper or the Woodchuck tongue twisters, but the one that kills me is “toy boat.”
Imho, pronunciation is purely mechanical. If you set your mouth, throat, tongue, lips and breath correctly, you can pronounce anything. Therefore, I am beginning to think there’s a cognitive process going on that causes tongue twisting.
What’s the dope?
I dunno about it being a cognitive process slippin’ its cogs SuperHal - try “unique New York” and see how you do. THAT is a killer for me; my brain seems to get it, but my tongue sure don’t.
Seems to me rapid repetition of the “oy” sound reinforces the neural pathway for that sounds and makes it more likely the “oa” sound will be pronounced incorrectly. While some tongue twisters are more difficult to say even once, the way some muscle sequences are more complicated to perform than others, I have trouble saying to “toy boat” repeatedly even though it’s easy to say it once.
Since the brain is involved in speech as well as the muscles themselves, surely every tongue twister has “a cognitive process going on…”.
I think the most difficult tongue-twisters have recurring sounds that are similar, but not the same. “Peter piper” just repeats the “p” sound, so isn’t much of a problem. But “toy boat” alternates between two similar sounds, “oy” and “o,” producing confusion. It also may have something to do with “lip” sounds vs. “tongue” sounds.
I’m sure a linguist can explain this much better than I can.
I find the T is part of the problem as well. Take out the final T, and it’s much easier.
Plus, I find I want to repeat the /oʊ/ sound of boat, not the /oɪ/ sound of toy. To be exact, I tend to want to convert them both to /o/. It’s that diphthong that is difficult.
Purportedly the hardest tongue twister ever:
The sixth sick sheikh’s sixth sheep’s sick.
This is the story about a poor little snake named “Petey.”
Petey was a snake only so big. Petey lived in a pit with his mother. One day Petey was hissing in the pit when his mother said, 'Petey, don’t hiss in the pit, go outside the pit to hiss." So Petey went outside of the pit to hiss…
That one only seems to trip me up if I don’t think about saying every word deliberately.
A nice two-person tongue twister is to have one person quickly saying “Fuzzy Duck?” and the other quickly responding, “Ducky Fuzz!”
You did read the entire story, not just my abbreviated preview, didn’t you?
I had a grandma, a speech and dramatic arts teacher, who used to hold her high school class at attention by reading Petey the Snake out loud to them. Nothing could thrill the students more than to have their teacher accidentally say the wrong and naughty words, but she was very good and it never tripped her up.
Part of her skill was to read the story very slowly and deliberately, just taking her time. No problem.
I think it has to do something with the mind too, because I can say Boat Toy all day long, but as soon as I try to say toy boat, I get all muddled.
IANAL (linguist 
)
In English, at any rate. That’s the only one that really gets me.
There’s this Czech one that’s pretty rough: strč prst skrz krk.
Or this Polish one: W Strzebrzeszynie chrząszcz brzmi w trzcinie.
Look up “metathesis” and “spoonerism”. We did a whole section of slips of the hands in Structures of Sign Languages in college. I found it extremely interesting. Apparently, the deaf community has “hand twisters” or “finger fumblers”. The phrase “good blood, bad blood” is a famous example.
In English, it’s possible to make 8 types of errors:
Shift (She want to makes it)
Exchange (I’m not as think as you drunk I am)
Anticipation (Are you ever going to bay be back?)
Perseveration (Are you ever going to pay me pack?)
Addition (Explain that clarefully, please)
Deletion (There are 8 kinds of sips of the tongue)
Substitution (Congress consists of the Senate and the House of Sandwiches)
Blend (man + boy = moy, e.g. I saw the moy run that way, officer!)
In some cases, whole words are messed up, like “think as you drunk”. Sometimes, it’s just a single sound, like “clarefully”, but it can be even less than that. Sometimes, it’s only one property of a phoneme that gets added, deleted, switched, or whatever.
“Cold boat” can become “Gold pote”. “That very boat” can become “That berry vote”. In the first instance, only the voicing switched places. The C is normally unvoiced and B is voiced. In “gole pote”, the C became voiced (and thus a G) while the b became unvoiced (and thus a P). In the second example, the fricative V and the bilabial B switched with each other.
So there’re some properties of slips of the tongue and hopefully that sheds some light on “how tongue twisters twist your tongue”.
Notice also that slips are more common when it results in an actual word or at least a possible word. You’ll never see “really moot” become “really mroot” because /mr/ isn’t a possible initial morpheme. You might expect, however “Cold gate” to become “Gold Plate” if the voicing of the initial phonemes were to be exchanged. This, of course, depends on the language that the twister is using.