说话 is complete on its own. Nothing needs to follow. 他现在说话。- He is currently speaking. 说... is followed by an object which usually answers "What did he say?" 她说她不喜欢吃芒果。- She said that she doesn't like eating mangoes. If we were to break down 说话， 说 is like "say" and 话 is like "words". In the literal sense, it means "to say words." This is why it's complete. If we just use 说... we're lacking the object. It's similar to "I said..." or "I say..." also lack objects.