Merry Christmas

Danistahohihv (Merry Christmas in Cherokee)

Buon natale (Merry Christmas in Italian)

Happy Christmas

I know it in Welsh and noticed a couple of years ago that Breton looked quite similar. I just now speculated that perhaps Cornish would also be similar (all 3 are classed as Brythonic languages) so :

Nadolig Llawen (Welsh).
Nedeleg Laouen (Breton)
Nadelik Lowen (Cornish).