Interesting statistics, thanks for sharing!
Living in a Spanish-spoken country, I may try to get to an explanation, altought you probably figured it out: first it´s a rather intuitive game, and no special language needs are used in it. Second, English is rather frecuent as a technical language, and probably most BB users know enough words to understand the level of EN used in XB.

However, if your application would have more language involved, and more complex interactions with the users, certainly the level of English understanding required will jump and having it (well!) translated is a must.

Cheers!
Sebastian @mobilenik.com