I dindt found one but I can only say that the sounds that make are like words... Check this interview ( to a zombie)

Me:Whats your name???

Zombie:Jackkk!!!!!

Me:Jack what?

Zombie: Dead dead deaaaddddd!!!!1

Me:Oh Jack Dead how old are you?

Zombie:Seaightttt!!!

Me:Six????

Zombie: Treeeaaaaa!!!!

Me:Ohh right... whats your job

Zombie: Uhhhh jackkk narrrrr!!!!!1

Me:US Navy???

Zombie:Jakkkk!!!!

I guess Jakkk means yes, you can do this by getting close to him( round 1 because at round +3 will attack, thats the way of doing the sounds, but he will go pissed and run to kill you)

In youtube (is of COD 5) are videos of talking zombies that says: monkey, playtime, Sam, retarded(LOL OMG) and some commented that a this COD a zombie madke the same sounds and one posted that one zombie at this COD say cookie...

Well who knows?? Maybe can be a error of saving sound (Monkey bomb says Sam, playtime I guess) and the monkey stuff of Samantha ghost(she says Dont hurt Mister Monkey, MISTER MONKEY JUST WANTED TO PLAYYY!!!!) but the retarded and cookie stuff, well I DONT KNOW OF WHERE THEY GOT THAT...

If you found one comment!!!!

And remember people:

I WILL EAT YOUR SOUL LOL

-Cristoforus28