Final answer:
The repetition of initial consonants is known as alliteration, a literary device that adds a rhythmic or musical effect to language. Consonance and assonance are similar concepts, involving the repetition of consonant and vowel sounds, respectively, but are not restricted to initial sounds.
Step-by-step explanation:
The repetition of initial consonants is called alliteration. It is a literary device where multiple words in a row start with the same consonant sound. An example of alliteration is the phrase "Away from the steamy sidewalk, the children sat in a circle." This occurs not only with consonants but can also involve vowel sounds. Alliteration aims to create a rhythmic or musical effect in poetry or prose.
In contrast to alliteration, consonance involves the repetition of consonant sounds at the end of words or within words, and it can create a slinking or smooth sound. For example, "the slithering snake shakes its little rattle" is an an instance of consonance. Unlike alliteration, consonance does not necessarily have to be at the beginning of words.
Another related concept is assonance, which is the repetition of vowel sounds within a word or phrases, such as in Edgar Allen Poe's "Once upon a midnight dreary, while I pondered weak and weary..."