They mean the language used by the majority of where they live, not the language used in the group. Even if all the members are native English speakers, this is still some way of keeping plausible deniability in terms of location.
Edit: reading the OP more cautiously, I think it’s unlikely the group lives in a place where English isn’t the majority language so the phrasing is vague for not reason. Plausible deniability went out of the window given all the information available.
That’s a curiously unspecific way to express this. Is your “majority language” not English?
They mean the language used by the majority of where they live, not the language used in the group. Even if all the members are native English speakers, this is still some way of keeping plausible deniability in terms of location.
Edit: reading the OP more cautiously, I think it’s unlikely the group lives in a place where English isn’t the majority language so the phrasing is vague for not reason. Plausible deniability went out of the window given all the information available.
We’re guessing, but I disagree. I think this group is not from an English-speaking country.