Repetition is the use of the same word or phrase multiple times in a piece of writing or speech. For example:
> "I went to the store, and then I went to the park, and then I went to the library."
Alliteration is the use of the same consonant sound at the beginning of multiple words in a piece of writing or speech. For example:
> "Peter Piper picked a peck of pickled peppers."
So, while both repetition and alliteration involve the use of similar sounds, they are not the same thing. Repetition involves the use of the same word or phrase, while alliteration involves the use of the same consonant sound.