Literature & language

Duolingo   Learn languages completely free, without ads or hidden charges.

Guide to Grammar and Writing  has definitions and examples of grammatical terms and essay construction.  Great for students writing papers needing a little extra help.

MLA Style and Format provides examples and explanations of the MLA (Modern Language Association) formats for writing papers.

Novelist Plus 
Novelist Plus helps readers of all ages or those who help readers find fiction and non-fiction books they will enjoy. Using simple search techniques, find helpful resources such as expert reading recommendations, read-alikes, book discussion guides, thematic book lists and more.