"Hun kinderen spelen."
Translation:Their children are playing.
Why is hun used instead of zijn? As in, Zijn kinderen spelen. Would it be because of the word kinderen?
"hun" is plural: "their"
"zijn" is singular: "his"
Note that singular and plural refer to the thing or person that owns, not to the thing or person that is being owned.
"Zijn kinderen spelen." is a correct Dutch sentence, but not a good translation.