Would like to join this campaign, but is it still valid that no posts may be made in local language?
-Posts that are made on local boards and not made in English will be denied (as I don't understand what they say).
You can make posts in local boards, but they don't count for the campaign. All your posts in local = 0, so make sure to have at least 15 in valid places.
Consider that there are other invalid boards, such as
Serious Discussion because no signatures are shown there. You can still make posts there, but they don't count for the signature campaign.