Questions & Answers about आज जन्मदिन है।
- आज = today
- जन्मदिन = birthday
- है = is
A very literal translation is Today birthday is. Natural English rearranges that to Today is the birthday or, more naturally in context, Today is [someone's] birthday.
Hindi usually puts the verb at or near the end of the sentence. So instead of English Today is birthday, Hindi gives आज जन्मदिन है = Today birthday is.
That is a very normal Hindi pattern:
- time expression first: आज
- noun/predicate: जन्मदिन
- verb at the end: है
Not by itself, at least not as clearly as English does.
If you specifically want Today is my birthday, the full and most natural sentence is:
- आज मेरा जन्मदिन है।
The shorter आज जन्मदिन है। can work if the context already makes it obvious whose birthday you mean, but on its own it feels incomplete to many learners and often to native speakers too.