RIDDLES AND TONGUE TWISTERS

To improve your pronunciation skills and have fun at the same time, here you have a couple of tongue twisters:

First an easy one:
I saw Susie sitting in a ​sh​oe ​sh​ine ​sh​op.
(Be careful with the sound /sh/)

Now a classic tongue twister called Peter Piper:
Peter Piper picked a peck of pickled peppers. Did Peter Piper pick a peck of pickled peppers? If Peter Piper picked a peck of pickled peppers, where’s the peck of pickled peppers of Peter Piper pecked?

And now a riddle for the bravest students: 
What English word has 3 consecutive double letters?