What Language(s) to be Used in Forum(s) ?

[Bernie]

HI,
May I ask what language is the preferred language of the forum?

I ask, as I thought it was English but of late I see more and more posts in differing languages and
also being answered in the same language.
I suspect ( and is only a suspicion) that this may be of limited use to many users.

Can we stick to one language please?
As English is the only language that SR uses, can we just use English, please?