To say your birthday in Engpsh, you can use the following sentence structure:

"My birthday is on [month] [day]."

For example, if your birthday is on January 1st, you can say:

"My birthday is on January 1st."

If you want to include the year of your birth, you can say:

"I was born on [month] [day], [year]."

For example, if you were born on January 1st, 2000, you can say:

"I was born on January 1st, 2000."

It is also common to use ordinal numbers to indicate the day of the month, such as "1st," "2nd," "3rd," etc. So, you could also say:

"My birthday is on the [ordinal number] of [month]."

For example, if your birthday is on January 1st, you could also say:

"My birthday is on the first of January."