Can you do Levi’s love language pleaseee!
I'm going to write it in the most canon-able way, so Levi never really had a romance and you are his first-ever partner.
Giving: Act of service - quality time - Word of affirmation
receiving: Quality time - Word of affirmation - Physical touch
Levi's love language is tricky at first. You need to get to know him to fully understand his action and recognize his act. His primary love language is act of service. Mostly because at first he wouldn't know how to deal with his feeling and would want to make you happy, so his first instinct would tell him to be useful. It can be just bringing you a cup of tea, cleaning your room or laundry if you are too busy, helping you to put the ODM. This one is closely related to his other big love language, quality time.
At first, Levi would be torn between, spend most of his time with you, or ignoring you. This poor boy bottled up his emotion since his born, and now he's dealing with an emotion that he barely knows, no to mention that he barely knows how to handle it. A part of him is euphoric, he wants to spend his whole time with you, get to know all of you, it the beginning, he's discovering the effect of being important for someone (in a romantic way). But the other part of him is afraid of everything that could go wrong, plus he doesn't want people to know you are together so he can't really spend his whole time with you. That's why quality time is important in your relationship. It can be just you two doing your paperwork together in silence or a moment when both of you can just be a couple, without talking about your work but just you. It's important for him to have a quiet space just the both of you to be out of his crazy life in the survey.
As much as people know Levi, they all know how rare compliments can be. His training are known to be rough and hard, and even if he does give some compliments they are only work-related. But with you, he always finds something nice to say, in his own Levi's style. Like if he like your hairstyle of the day he would casually say something like "Likes the stuff you did to your hair" with pink dust on his cheek. It's also caring for you, a mix like act of service and praise, he would run you a bath and tell you to get some rest in it because you did really great this week at work.
I know you're probably thinking that Levi already gets plenty of words of affirmation by being called "the strongest" by everybody. But you will get a puddle if you tell him how pretty he is. Again, he wasn't used to being praised (except in his work but does it really count? not it's not you.) And having his partner say sweet things to him makes him blush. Tell him how you love it when he makes you tea, or when you just spend time with him like cooking or going for a walk. Praise him for something he's not used to be praised and his heart will be flustered
And finally, Levi is touch-starved. I will probably fight everyone who says otherwise because I could bet that (if you are in couple he trust you with his whole heart) you just have to run your hand in his hair and he melts to your touch. At the beginning of your relationship, he would be hesitant and probably never initiate, but he loved holding your hand, love cuddling before sleeping. But what he prefers the most are your kiss on his cheek. Obviously, it's in his Levi's way, nothing outside the closed doors because he doesn't want people to know. And they are times for love and cuddles and time for work. Levi like thing well organized and so does with his schedule.