These sentences are called tongue twister.
Repeat these sentences 3 times and have lots of fun:
Peter Piper picked a peck of pickled peppers.
I saw Susie sitting in a shoe shine shop where she sits she shines, and where she shines she sits.
Sheena leads, Sheila needs.
I wish to wish the wish you wish to wish, but if you wish the wish the witch wishes, I won’t wish the wish you wish to wish.
I scream, you scream, we all scream for ice cream!
She sells sea shells on the sea shore.
How many cookies could a good cook cook if a good cook could cook cookies? A good cook could cook as much cookies as a good cook who could cook cookies.