"ʻO ka Pōʻahia kou lā hānau?"

Translation: What day of the week is your birthday?

[ThomasVea]

Thought it would be okay to say "On what day is your birthday?", but it wasn't so.

[GeraldMath4]

To be on the safe side, I added "of the week" after "What day." Didn't work.

[Mak511906]

Neither did "What date." =(

[Mak511906]

Just curious - why is "When is your birthday?" wrong? Because it doesn't specify a date in the answer?

[Bob746503]

In English, we are more likely to "On what day of the week is your birthday?" than to say "What day of the week is your birthday?"