World's Hardest Tongue Twister — Dr. Luke Shellenberger
MIT Researchers Reveal The World's Toughest Tongue Twister! - Kids News Article | KidzNews
75 Tongue Twisters for Kids & Adults - Hard & Easy Ones - Parade: Entertainment, Recipes, Health, Life, Holidays
History Unboxed - Wednesday's Words: We've had a fun time looking back over the history of tongue twisters, but what is the most challenging tongue twister? There's not currently an official answer.
Lot - Hardest Tongue Twister Museum Display Guinness World Record