Zombie Pigmen sounds not playing

General Information

https://dump.viaversion.com/68a6b186800ba7dfc5408e75ec51c60a7fef5b6d8cd56010ca170f60738f8944

Bug Description

Zombie Pigman sounds fail to play.
The minecraft console log shows warnings like [Render thread/WARN]: Unable to play unknown soundEvent: minecraft:entity.zombie_pigman.ambient

Can be fixed with a resource pack
assets/minecraft/sounds.json:
sounds.json

Steps to Reproduce

1. Join a 1.8 server
2. Go to the nether
3. Find a zombie pigman

Expected Behavior

Zombie pigman should play sounds on idle, when angered, attacked and killed.