In 2013, researchers at MIT’s Research Laboratory of Electronics declared “pad kid poured curd pulled cod” the hardest tongue twister in the world after it caused more speech errors than any other phrase tested. We collected 12 of the most brain-bending tongue twisters in English – with explanations for why each one trips you up.
1. Pad Kid Poured Curd Pulled Cod
“Pad kid poured curd pulled cod”
Repeat it 10 times as fast as you can. MIT researchers officially named this the world’s hardest tongue twister after testing it against other candidates. The phrase combines alternating plosive consonants – /p/, /k/, /d/ – with a liquid /r/ in patterns that cause competing speech motor plans to collide. Most people either grind to a halt or dissolve into nonsense after three attempts.
2. The Sixth Sick Sheikh’s Sixth Sheep’s Sick
“The sixth sick sheikh’s sixth sheep’s sick”
Often cited in the Guinness World Records as the hardest tongue twister in the world. Six different sibilant and fricative sounds – /s/, /k/, /ʃ/ – compete across a grammatically complex possessive chain. The possessive apostrophes don’t help: your brain must track “whose sixth sheep” while your mouth is already failing on “sixth sick.”
3. Irish Wristwatch
“Irish wristwatch, Swiss wristwatch, Swiss wristwatch, Irish wristwatch”
“Wristwatch” alone combines /r/, /w/, and /tʃ/ in a three-consonant cluster that most native English speakers stumble on. Prepend “Irish” – another /r/ immediately before – and most people default to “rishwatch” within two repetitions. Add “Swiss” and the /w/ softens into /v/ almost immediately.
4. The Seething Sea
“The seething sea ceaseth and thus the seething sea sufficeth us”
A nearly pure /s/ and /θ/ alternation. Both sounds are produced with the tongue near the upper front teeth – the difference is only whether the tongue is behind them (/s/) or between them (/θ/). At speed, the mouth stops tracking the distinction and everything merges into a single prolonged lisp.
5. She Stood on the Balcony
“She stood on the balcony, inexplicably mimicking him hiccupping and amicably welcoming him in”
This one trips people up differently: multi-syllable words with similar stress patterns. “Inexplicably” and “amicably” look similar in print but require completely different mouth movements. By the time you reach “welcoming him in,” your tongue has already given up on accurate vowels.
6. Rubber Baby Buggy Bumpers
“Rubber baby buggy bumpers” (x5)
The /r/ in “rubber” prepares the ear for another /r/ – then every subsequent word starts with /b/ instead. The brain keeps predicting /r/ and getting /b/, then overcompensates and predicts /b/ when “rubber” comes around again. Most speakers start dropping the /r/ entirely within three repetitions.
7. Pre-Shrunk Silk Shirts
“Pre-shrunk silk shirts” (x5)
Four consonant clusters in four words. “Pre-shrunk” ends in /k/ and “silk” begins with /s/ – the transition causes the /l/ in “silk” to drop out. “Shirts” then arrives with its own /ʃ/-/r/ cluster and there is nothing left for the tongue to do but give up.
8. Unique New York
“Unique New York, unique New York, you know you need unique New York”
The /juː/ onset in “unique” and the /nj/ in “New” alternate in a way that makes “unique” sound like “you need” after three fast repetitions. The final line adds “you know you need” – nearly identical in mouth shape to the phrase itself – and everything merges.
9. Toy Boat
“Toy boat” (x10)
Deceptively simple. The diphthong /ɔɪ/ in “toy” leads into /b/ in “boat,” then the /t/ in “toy” returns. After three clean repetitions, “toy boat” starts morphing into “troy boat,” “tow boat,” and “boy tote.” Most people stop at five.
10. Red Lorry Yellow Lorry
“Red lorry, yellow lorry, red lorry, yellow lorry”
A classic British twister. The alternation between /r/ in “red” and “lorry” and /l/ in “yellow” creates exactly the kind of similar-but-different motor sequence that speech research identifies as most disruptive. “Lorry” itself contains both sounds, making it doubly treacherous.
11. Theophilus Thistle
“Theophilus Thistle, the successful thistle sifter, in sifting a sieve full of un-sifted thistles, thrust three thousand thistles through the thick of his thumb”
One of the longest and hardest in the English canon. Every key word contains /θ/ or /s/, and “sifter,” “sifting,” “sieve,” and “un-sifted” arrive in rapid succession. “Thrust three thousand” at the end requires three /θ/ sounds followed immediately by “through” and “thick.” Good luck.
12. Good Blood Bad Blood
“Good blood, bad blood, good blood, bad blood”
The /ʊ/ in “good” and /æ/ in “bad” are easy individually. The consonant cluster /bl/ followed by voiced /d/ in both words causes them to merge at speed. Most speakers arrive at “gub lud, bab lud” within three repetitions. The symmetry of the phrase is exactly what makes it impossible.
Tips for Tackling Hard Tongue Twisters
- Go slow first: Say each word clearly at half speed before attempting full pace. Your mouth needs to learn the sequence before it can execute it quickly.
- Isolate the hard cluster: Find the two or three syllables that keep breaking down and drill them as a mini-twister before running the whole phrase.
- Exaggerate the mouth movements: Overstate each consonant when practicing. The exaggeration teaches precision; speed comes naturally after that.
More Tongue Twister Challenges
- All Tongue Twisters – the complete collection
- Funny Tongue Twisters – hard AND hilarious
- Long Tongue Twisters – endurance challenges
- Tongue Twisters for Adults – premium challenge level
- Short Tongue Twisters – quick-fire practice