Even though Dullahans do not have a head they do have the innate ability to speak through their ghostly wails as if it comes from the wind. Dullahans, however, do not need to eat, drink, or sleep because of their undeath. 

One of the most common things that Dullahan shares is the fact that instead of the head they have a flame this flame can come in any color size or shape however it is a real Flame that can burn people you gain the Firebolt cantrip and at level 3 you gain the burning handsspell two times before a long rest. you also have thecontrol flames spell only on your Etherial Flame you use con as your casting modifier

Because of the dull hands undeath they have the ability to resist death because there spirits to cling to their bodies. You gain an advantage on death saves.