How many is 1 alliteration?

"Alliteration" is a literary device, not a quantity. It refers to the repetition of consonant sounds at the beginning of words in a phrase or sentence.

So, there's no such thing as "1 alliteration". You can have a phrase with one example of alliteration, such as "Peter Piper picked a peck of pickled peppers". There, the "p" sound repeats in the first three words.

You can also have a sentence with multiple examples of alliteration, like "Sally sells seashells by the seashore". There, the "s" sound repeats in the first four words.

Let me know if you have any other questions!