The English Page provides a comprehensive set of tutorials which include interactive quizzes. These can be used for independent or instructor lead learning sessions. Start with the Verb Tenses to get a good feel of the resource.
Soapmaking truly is an artform and it was hard to just pick a few sellers from Folksy to showcase for this section. I've bought soaps from a few of these sellers (and can't wait to buy from the rest) and they really do feel and smell as good as they look.