Easy:
* Tonya's tiny toy train tootled.
* Tonya took two tacos to the town.
Medium:
* Tony the turtle taught Tonya to talk.
* Tonya's ten tiny tulips tumbled to the ground.
Hard:
* Two tiny toads taught Tonya to tap.
* The terrific Tonya traded tiny toy trucks for two tall trees.
You can get creative and make your own, too! The key is to use sounds that are difficult to pronounce quickly, like "t" and "n," and repeat them frequently.