In at least England and probably some of the Commonwealth (once and/or conquered by Britian) countries that speak English (not Canada I know), and maybe a few others.
they just say HAPPY CHRISTMAS
Americans say: "Merry Christmas" and people from England say: "Happy Christmas".
The translated way to to say Happy Christmas in the Malyalam language is "Happy Krismas."
Have a happy holiday! Or have a happy Christmas
To say Happy Christmas in Punjabi you simply say "khuśa krisamasa".
Just as in your question !They tend to say "Happy Christmas" instead of "Merry".Merry Christmas
"Merry Christmas, mate!" English is the predominant language in Australia, so you say it in exactly the same way except with the addition of an Australian accent. Or: Usually you just say "Merry Christmas" or "Happy Christmas". In the vernacular, you might say, " 'Ave a good one, mate."
Happy Christmas
You say "Merry Christmas" in Mexico as "Feliz Navidad" or "Happy Christmas."
We say Merry Christmas or Happy Christmas
The official language of Australia is English so you would say "Merry Christmas"
Just a mattter of where your from really. Americans say merry whereas British folks would say happy.