In addition, like several Legendary Pokémon, Shaymin were revealed to be able to communicate telepathically. In Japanese, its voice sounds like that of a little child, and it says deshu (Land Forme) or desu (Sky Forme) at the end of almost every sentence.
(and yes I made that. This morning. Ask Commander Saturn if you don't believe me.)
If you don't get it, you don't belong on the internets.