School for Expat's childrens (Amsterdam)

Hi Guys,
I need to ask a question. We are thinking to relocate to Amsterdam from Istanbul Turkey. We have two boys, 1 and 5 years old. Our 5 years old boy can understand and speak basic English (very little). How can our 5 years old boy be included to government school in the Netherlands. International schools are very expensive but government schools are free. We choose government school but how can we defeat the language problem? Anyone can help me appreciated.
Kind Regards,
Cagatay