Tongue Twisters are lots of fun (and difficult). They often don't make much sense, but they certainly exercise your pronunciation muscles. Four tongue twisters are listed below. Click on the link to go to the tongue twister and recording, listen as often as you want, and give them a try on your own!
Peter Piper
Betty Botter
Sea Shells by the Sea Shore
A Flea and a Fly
Woodchuck

