Why...

I dislike when some people especially on twitter think I can speak Japanese well because my muse is Japanese and most of my muses are bilingual or trilingual at least for exile tribe’s case. I only use ENGLISH while roleplaying because it’s a universal language and someone  on twitter changed their fc to a korean idol that can speak Japanese so they can use Japanese should I be scared ?  

Edit 1: I know not everyone knows English well but this person told me they edited their computer’s languages to Japanese , French and Spanish. I’m seriously worried.