Formal:
* শুভ বড়দিন (Shubho Boro Din) - This translates to "Happy Big Day" and is a common way to wish someone a Merry Christmas in Bengali.
Informal:
* বড়দিনের শুভেচ্ছা (Boro Diner Shubhechcha) - This translates to "Christmas greetings" and is a more casual way to wish someone a Merry Christmas.
Religious:
* ঈসার জন্মদিনের শুভেচ্ছা (Isar Jonmodiner Shubhechcha) - This translates to "Greetings on Jesus' Birthday" and is a more specific and religious way to wish someone a Merry Christmas.
It's important to note that the use of these phrases might not be understood by everyone in Bangladesh, as many people may not celebrate Christmas. It's always a good idea to consider your audience and use a phrase that they would understand.