I find it very interesting how my 13 year old daughter will stand over my shoulder when I am typing emails or instant messaging and correct my spelling and punctuation. As an unschooler who has always followed a child led education, she has never had one lesson on spelling or punctuation in her life, but is an excellent speller and knows exactly where and when to use punctuation.  (More so than mom I guess.)  Unschooling really does work. Trust your kids to learn and amazing things do happen.