Final answer:
The phrase 'Peter Piper picked a peck of pickled peppers' exemplifies alliteration due to the repeating 'P' sound at the start of several consecutive words.
Step-by-step explanation:
“Peter Piper picked a peck of pickled peppers” is an example of alliteration. Alliteration is a literary device that involves the repetition of initial consonant sounds in multiple words that are in close proximity. In contrast, assonance involves the repetition of vowel sounds within words, while consonance refers to the repetition of consonant sounds at the end of nearby words, and onomatopoeia is the use of words that imitate the sounds they describe. This tongue twister contains alliteration because the initial 'P' sound is repeated in the words 'Peter,' 'Piper,' 'picked,' 'peck,' and 'pickled.'