If your child speaks Afrikaans it takes about three weeks to get used to the Dutch accent, thereafter your child should be able to deduce what is said to him/her if the speaker speaks slowly and with a few hand gestures.
0-2 years old;
For young children (under age two) there is no impact. They are only starting to learn communicating themselves and it is astounding how fast they pick up the “foreign language”, sometimes even better than their mother tongue.
2-5 years old
For children 2-5 years of age I dare say the same as above. The only difference is that their friends will sometimes notice (and rarely comment) that they speak “with a different voice”, but they leave it at just that and play on. It seems that play really has no language. The Dutch are very open to other cultures/languages and mostly regard it important to teach their children from a young age to respect others and find a way to befriend them regardless of their differences.
5+ years old
For children 5 and up it may be a little more difficult as communication skills are usually a little stronger by then and they also start relying on language more during playtime and in school. That said, I quote the above: “The Dutch are very open to other cultures/languages and mostly regard it important to teach their children from a young age to respect others and find a way to befriend them regardless of their differences.” Teachers go out of their way to engage a child not only in class, but on the playground as well. It also helps if you enrol your child in extra-curricular activities such as football, swimming, dance classes, etc. so that they will have more exposure to the language and their peers.
Try practicing the alfabetlied with your kids!