The Convention does not demand the court to talk to the minor. However, EU countries (exept Denmark) are bound by the Brussel II bis regulation. Article 11 of his regulation states that in an abduction court procedure, the child must be given opportunity to be heard.
In normal family court procedures in the Netherlands, courts normally invite children of the age of 12 and above to give their opinion, in a letter of through a short child interview with the judge(s). The judges will be wearing their normal clothes and they will adjust to the age of the child. The parents and the lawyers will not be present. The guardian ad litem can be present to support the child.
In abduction procedures, the limit is lowered to 6 years and above. Parents can specifically ask the court to invite their child, if it is under 6.