“언제나” = “언제” + “-나” According to the Naver Korean dictionary, “-나” has lots of meaning. I think this is what you are looking for. ((받침 없는 체언이나 부사어 뒤에 붙어)) 여러 가지 중에서 어느 것을 선택하여도 상관없음을 나타내는 보조사. One of –나’s definition here is that it doesn’t matter whatever you choose among a lot of options. Ex) 그런 걸 아무에게나 물어볼 순 없잖아. (We can’t just ask anyone that.) Furthermore, it is often used to explain the situation or one’s attitude to staying the same without any changes from start to finish. Ex) 그는 자나 깨나 그녀 생각뿐이었다. (Awake or asleep, he thought only of her.) Ex) 눈이 오나 비가 오나 그는 일을 한다. (He works whether it snows or rains.) As a result, adding –나 to 언제, it becomes always. It means that things are not changed or going to stay the same whenever, which date you choose. I hope this could be helpful to you. And I am sorry if there are some grammar mistakes which can make you confused. Please feel free to contact me if this is not working for you.