How do you say Merry Christmas in Flemish?

Merry Christmas in Flemish is "Zalig Kerstfeest" pronounced "Zaa-lig Kherst-feest".

It literally translates to "Blissful Christmas Feast."

You can also say "Frolijke Kerst" which means "Merry Christmas".

Keep in mind that Flemish is a dialect of Dutch, so these phrases will be understood in the Netherlands as well.