I'm told (but have no direct knowledge) that many police dogs in the US are trained to german commands. This is because previously (and in some cases still) police departments used dogs trained in Germany and they have continued so that there is continuity of commands (ie you don't have to know which dogs speaks which language).
Yes, this is true. Many personal protection dogs as well.
Sometimes it's Dutch instead, but that's true.
Many agencies, especially those new to having K-9 or small departments that may not be able to spend time dedicated to training from puppies, get dogs from Europe that are partially or fully trained. The lineage of the working dog breeds is much better in Europe because many breeds have bloodlines that haven't been bred for generations to be pets (like here in the US).
It's also why agencies pay so much for the dogs. Last I heard (I used to be more involved volunteering with my local PD) a fully trained dog was around $25k, USD, a partially trained was something like $8k - $10. It sounds like a lot until you realize a fully trained dog is 18—24 months old when acquired and has been training every day during that time.