To promote the release of the upcoming games
Pokémon Black Version 2 and Pokémon White Version 2, the official Pokémon YouTube channel has posted the English dubbed version of the
animated trailer that was released a few months ago in Japanese. The version posted also includes the battle scene between the female protagonist's
Serperior and Cheren's
Stoutland. Below is the video.
Source:
http://www.youtube.com/user/pokemon