Cumpleaños felices

[Stu]

I have been looking at a Yabla video of someone singing Cumpleaños feliz, on the last repetition he sings cumpleaños felices.

What the purpose of that?

[Rusty]

There are several ways to sing Happy Birthday. If this person is a native speaker of the language, he is using cumpleaños in the plural, hence the agreement of the adjective. Perhaps more than one person was celebrating.

[AngelicaDeAlquezar]

I agree... or they're wishing one person many happy birthdays for the future, which means they'd be wishing that person a long life. :)

[Stu]

Thank you both - very good.