Speaking in Mother tongue

I just got a short question about speaking in mother tongue that bugs me since a half year now.
Do I have to speak the Spells,Incantations,evocations and all the other mantra related stuff in my mother tongue(which is not english) or can I just pic the Language that I´m most comfortable with ?

General stuff like spells- the language you feel most comfortable with. Just out of interest- what would that be if not your mother tongue?

Specific mantras and incantations- the language they’re given in.