hi anon! dont worry about it, id love to talk more about!

youre right in that they dont have anything SUPER unique going on in their japanese so theres not much for me to analyze in that manner. they do have differences between them though!

i mentioned it in my muneuji answer but muneuji and yukikaze speak kinda similarly in the sense that both of them speak in a masculine, firm, and mature tone, but yukikaze isnt quite as formal as muneuji is. im actually VERY adamantly against making yukikaze speak incredibly formally (i think i just feel strongly about it as a yukikaze oshi HUDHTJRGF) because i feel like that just doesnt feel that way to me. hes polite, but hes not formal if you get me... like he wouldnt be the type to say "shall i help you prepare dinner," hed be like "would you like some help preparing dinner". if you ask me, he has a straightforward way of putting things, but not in a cold and blunt way, just in an honest way. thats why his weird compliments and words of affection sound so shocking coming from him, because he cuts no corners KUERHJGDF.

kafka on the other hand (especially when he talks to shunin) is more hmmm... i wouldnt say cutesy (but he does get like that on rare occasion with shunin) but more down-to-earth i suppose? and definitely playful at times. when he's in business mode though he definitely has this air of confidence about him. i dont do anything particularly special with the way he speaks but i do try to pay attention to writing him when he speaks business because i want to use phrases and wordings that make him sound like the confident leader he is when hes like that!