why would she wonder what a wedding is but know what a wedding dress is? are they using some obscure word or alternative spelling in the original language?
The chapter is still free on comic walker right now so I checked out the raws (I don't know if they'll do the thing where after a certain amount of time or chapters older ones will become locked, although it does seem to be normal for the first three or so to stay free): https://comic-walker.com/contents/detail/KDCW_KS12202158010000_68
And no, they just use the regular word for marriage unobscured in any way so it's just a bit of a plot hole unless this:
I’m waiting for the plot twist in which Tanya is actually an experienced witch unlike the naive and weak witch Melissa thinks she is lol
actually turns out to be true lol