Well usually in riddles they use the wrong word as to confuse the person answering (Just as matt did with the eagles question)
I don't know if that's a compliment or an insult, but I appreciate the recognition!
The key to a successful riddle is 1. Simplicity and 2. Omission. The "He spoke, she died. Why?" riddle is good with simplicity but not with omission. There is nothing to go on besides two beings and a single action each committed. They could literally be anything and could have done anything. "Spoke" could be a reference to a handwritten letter. "Died" could be a reference to losing a game. "He" could be Life and "She" could be a boat. Even with the hints ("Yes, Maybe they are"), we still have almost nothing to use.
My guess:
He was Death.
He was her boyfriend and she was cheating. He spoke her name and she died of shame.
He was supposed to be dead. When he spoke, she died of fright because she didn't know he was alive.
They were climbing a mountain. He spoke, causing a rockslide and killing them both.
They were soldiers hiding from the enemy. He spoke, giving away their position and she was killed.
They were prisoners. If one of them spoke, the other died. He spoke and the captors killed her.
She was doing something dangerous. When he spoke, she panicked and died as a result.
She was going to kill both of them out of revenge or some other reason, and he said "do it."
My question: Are all the elements (he, she, spoke, died) actual, physical being and actions, or are they metaphors?