In fact, per the Play! Pokémon VG Rules, Formats, & Penalty Guidelines, "Team lists should be completed using the language to which the player’s game is set." If you have a Pokémon in a foreign language, you should still submit your team list in the language to which your game is set.
To accomodate players around the globe, we've added multi-lingual support. Since you create your Pokémon first, before selecting Pokémon to be on your team, you select your language when you are adding or editing a Pokémon.
In the Pokémon Editor, you'll see a dropdown menu near the top with available languages: English, French, Italian, German, Spanish, Japanese, and Korean.
Simplified Chinese and Traditional Chinese are also available - however, we only have translations for the Pokémon names. The dropdown lists for Ability, Held Item, and Moves will display in English.