linguist_random_realm_effect

linguist_random_realm_effect = {
	# Save random culture realm to fetch faith
	if = {
		limit = {
			any_independent_ruler = { culture = scope:$CULTURE$ }
		}
		ordered_independent_ruler = {
			limit = { culture = scope:$CULTURE$ }
			order_by = primary_title.tier
			save_scope_as = $CULTURE$_ruler
		}
	}
	# Save fallback to fetch faith
	else = {
		scope:target_court_language = { save_scope_as = $CULTURE$_ruler }
	}
}

As written in game/common/scripted_effects/00_decisions_effects.txt.