Family Nmaes

I have a question about family names in MTW.
When your king or heir marries a foriegn princess is there a chance some of their kids will have foriegn names? Because I was playing as the spainish and my king was married to a hungarian princess and one of my princes ended up having the name "Istvan" is this normal? My friend, Lord Cazaric also said this happed a couple of times.


Oops, looks like I spelt names wrong, the title is supposed to be "Family Names"

Hmm, I´d place my bet on the "bug" option. Like the "CAN NOT DEFINE NAME" I get sometimes, as a name, for some reason. Specially with Spain and Hungary.