Where's Clefairy's Voice? (Japanese: ピッピのくるくるおんぷ Pippi's Spinning Notes) written by Kunimi Kawamura and illustrated by Kagemaru Himeno. In English, it is the 6th book in the Pokémon Tales series. In Japanese, it is the 15th book. It is 18 pages long.
Without a voice, Clefairy can't announce the time for all the other Pokémon!