"Siapa nama putra kalian?"

Translation: What is the name of your son?

[angelperak]

"What is your son's name?" should be accepted

[Deinonysus]

Accepted as of 12 September 2018, thanks for reporting!

[dkfour]

Yes, much less awkward

[HelenJVG]

How would you say "what are the names of your sons?"

[deactivated user]

No English speaker would ever say 'What is the name if your son?'
What's your son's name?