I've taken care of kids from birth to age 12, after that they are legally able to be home alone unless they are ill.
I am a mom of a teenager, though he doesn't live with me; but well before then I took care of two kids from Finland until the youngest turned12 yrs old then I only stayed with the kids when they were ill.
I believe in when the work is done depending on what the task is then we can have fun, this includes obeying parents when I'm not around, I'm kind and loving and I reward good behavior with outings to various places in town.
I do know a few words in Finnish as well as German and Arapahoe, but I'm not fluent in foreign languages. As the kids begin to reach 12 yrs old I can help with teaching life skills like cooking so that they are able to cook for themselves in their teen years and beyond as well as teach basic sewing skills since there's a lot of life skills no one teaches anymore as parents.