"Nigel: Can Harry speak Parseltongue when he is no longer a horcrux?
J.K. Rowling: No, he loses the ability, and is very glad to do so."
Oh and here's the confirmation from her that AD understood Parseltoungue.
"Delailah: How does Dumbledore understand Parseltongue?
J.K. Rowling: Dumbledore understood Mermish, Gobbledegook and Parseltongue. The man was brilliant."
Quotes taken from bloomsbury.com
17