Around the ragged rock the ragged rascal ran.
Alliterations are simply small pieces of poetry, generally nonsensical that sound funny to say. As a teaching tool they force the muscles in the mouth and tongue to practice the movements needed to speak a different language. The way the mouth forms the sounds is crucial for good language and the term used is how we enunciate our words. Many years ago one of my students was stressed due to a speech lisp she had.
She had the speech impediment for many years but some of her friends had started to tease her. I listened to her speech and felt if she gave the muscles of the mouth and tongue specific exercise it would help her problem. Four weeks later
after praciticing her sheets of alliterations twice a day her lisp had disappeared. I have noticed a rapid improvement in Thai students with the difficult "L" and "R" sounds. If I can get them to practice the alliterations, their enunciation of the "L" and "R" sounds, improves dramatically.
e·nun·ci·ate
"Someone should show Sylvia some strokes
so she shall not sink."
sheep should sleep in a shed.
but the big black bear bit the big black bug back!
some rubber baby-buggy bumpers.
were reared wrongly in a rural brewery.
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 Peter Piper picked?
It's slick to stick a lock upon your stock,
Or some stickler who is slicker
Will stick you of your liquor
If you fail to lock your liquor
With a lock!