A “virelangue” (ou “language breaker” ou “fork-tongue”) is a phrase (or a sentence or a small group of sentences) fun (amusing), characterized by difficulty in pronunciation or listening comprehension, or even both at the same time. 
It's a fun way to practice speaking.  
 By pair, CM2 students created their tongue twisters :  
A dog whines because he's hungry.
Andrea / Raphaël
If daddy is not there your
daddy will leave. Tristan / Eleanor
A
redhead pencil case under the heated seat. Clemency / Ilhane
Charlotte sings a song at the butcher's house. Clara
The crocodile bites a hollow and crunchy crab.  Clara 
We play cat with a pie
malabar. Kelyan / Noah 
Perlimpinpin eats bread
every morning. Faustina / Calvin
Charlotte sings sings a
singing. Jade / Morgan
If the snakes hiss
other snakes will hiss hiss hiss will be a melody.
Paul / Heloise
In a castle a knight rode his horse.  Martin / Gabrielle 
Martin matin mange du pain.  Martin / Gabrielle
A dog and a cat once bickered.  Martin / Gabrielle 
The snake often hisses without blowing. Elise / Leonie
If your sheep shear your sheep will be sheared.  Elise / Leonie 
If these six hundred snakes
come out tonight they will whistle under this dirty bag. Sarah
/ Constantin
This snake hisses hisses
whistle on this scepter. Leo / Louna
The serpent blows on the
dry sausage. Tom / Charlotte