The 6 year old's pronunciation is not perfect and I could see a lot of frustration when he was initially using it. The drive to use the device has driven him to take his time and really focus on pronunciation so he can play the song or video's that he likes.
They understand it's a computer. But we all tend to treat it as an assistant. A really touching moment was when he used the Home to call "Santa." After he finished that call and we walked away, I saw/listened in My Activity that he asked to call God.