You know the words that are repeated twice when saying them? They have a name : Onomatopoeia..but this is the first time I hear this name, so I like to call them the dokidoki words.
These are words that are taken from the sound they represent.
DOKIDOKI means heart beating quickly in excitement.
Other examples like KIRAKIRA:glittering , PERAPERA: speaking fluentlly, PIKAPIKA:sparkle
See these pages for more fun examples!