Train speech recognition for a second language

[MentalFS]

I've added a different language like described here, but it doesn't recognize my commands well.

Naturally, the solution would be voice training, but Windows will only let me train my main language. I've even set the preferred speech language to the new language, but that doesn't change anything. And I really don't want to set my whoöe system to the new language, as it would mess up a lot of other applications.