Easy:
* Peter Piper picked a peck of pickled peppers. A peck of pickled peppers Peter Piper picked. If Peter Piper picked a peck of pickled peppers, where's the peck of pickled peppers Peter Piper picked?
* Purple penguins prefer purple peppers.
* Peter picked a peck of pickled peppers.
Medium:
* Peggy's pet python picked a peach pit.
* Proper preparation prevents poor performance.
* The playful pup pranced past the park, paddling in puddles with playful paws.
Hard:
* Two tiny tigers take turns trying to tame a terrible, terrific tiger.
* Phillip's phenomenal phone photography produces perfect portraits of playful penguins.
* The playful pup, packed with passion, pounced upon the prickly pear, popping its prickly pod.
Let me know if you'd like more tongue twisters or want me to adjust the difficulty!