While there is no official English version, it does feature some English lyrics interspersed throughout.
Here is a rough translation of the song:
Verse 1:
(Japanese)
Shining bright,
The diamond and pearl,
Dreams of adventure,
Calling to me.
Chorus:
(Japanese)
Pokemon, Pokemon,
Strong and proud,
Together we'll explore,
Every land, every town.
Verse 2:
(Japanese)
With trainers at my side,
We'll face the unknown,
With courage and might,
The journey goes on.
Chorus:
(Japanese)
Pokemon, Pokemon,
Strong and proud,
Together we'll explore,
Every land, every town.
Bridge:
(Japanese)
Legends whisper,
Of ancient power,
New challenges await,
In every hour.
Chorus:
(Japanese)
Pokemon, Pokemon,
Strong and proud,
Together we'll explore,
Every land, every town.
Outro:
(Japanese)
Diamond and pearl,
Together we stand,
The Pokemon journey,
In our hand.
Please note that this is an approximation of the lyrics. The song mainly uses Japanese, but there are English words used in the chorus, such as "Pokemon," "strong," "proud," and "explore."
You can find the full lyrics on sites like Genius or Lyrics.com.