This is another one of those contradictory rules you've probably heard: Only ever use "said" in your dialogue tags. Yet you've also probably heard "said is dead." So which is it? The real answer is found in breaking both of these and finding a balance.

While using said is great for its invisible nature, other words can better describe the mood or volume you're trying to convey in fewer words than it would take to describe. As with most writing, it's about finding the right word rather than the one people say you should use, or not use.