the ducks have more of a " scratchy quack" of normal male ducks, but there is a difference between them talking and hissing. If its aggressive, it will hiss, stuck its feathers up, and put its head down low and spread its wings a little, trust me, you will know if it's upset with you.
I've a momma duck that hisses at me relentlessly and it's definitely not friendly; but some people do describe the talking as 'huffy' or 'hissing'