Police dogs have a tough job. They climb metal stairs in the dark, crawl through narrow tunnels, physically fight people when needed, and still have to be gentle enough to approach victims.
There was recently a police dog training meet in Oregon. To be certified, a dog needs to score 100 percent in a series of tests. That level of perfection requires around 200 hours for a drug dog, trained to sniff out drugs hidden in secret compartments, and around 360 hours for a patrol dog. The latter have physically tough jobs, are trained to track humans, and even sniff down objects a certain person has touched.
Many trainers use commands in another language, to make it easier for the dog to understand if a word is a command to do something, or said/shouted to a suspect. Many also uses different types of toys at home and as reward at work, to make it easier for the dog to know when it’s on duty.