He doesn't to always use word magic. And it's not the only power xiao wei has. He can just be using other powers of xiao wei. I think here it's a combination of xiao wei and baize powers.
It's from the demon lore. Basically demons are said to be genderless. She/ he has changed into so many faces along…
That's why it says loopholes. Using lores and it's rules to show your story. And xiao wei is in male form in the present when all the scenes are happening. That's enough to prove they aren't showing anything and gets a pass.
Here.
I think here it's a combination of xiao wei and baize powers.
https://x.com/i/status/2041028498404585906
Hope you are enjoying the drama. 😍