Do you want your children to expand their vocabulary and, more importantly, learn to continue to expand their vocabulary in the normal course of life more rapidly? Give them science fiction and fantasy novels to read. Science fiction and fantasy novels overtly place demands on readers that are implicit and beneficial in all literature: namely, the skill of learning word meanings from context.
Children reading a novel set in a familiar time and place may gloss over words they don’t understand because the general setting and flow of the story isn’t compromised. The story, even the specific sentence, still makes sense to them, or makes enough sense, even if they don’t know the meaning of a particular adjective or even verb. The story remains enjoyable and engaging despite words passing by, unknown. Though they will still benefit from the gradual expansion of their vocabulary, they won’t necessarily be overtly challenged to wrestle with the context to find the meaning.
Science fiction and fantasy novels are in your face. They focus on strange new settings and employ vocabulary that is often new or even made-up. If the reader is unwilling to puzzle out the meaning of words from their context, the story will simply drag to a halt and the enjoyment of the story will evaporate. Young readers want to enjoy books and will find their natural curiosity pushing them to decipher these strange or made-up words.
Like any skill, the ability to learn word meaning from context improves with practice. In my experience, the overt practice of this skill forced on readers by science fiction and fantasy translates into an improved passive ability to harvest new vocabulary from other literature. The child practices the skill on behalf of their enjoyment of the The Hobbit, and goes on to more effortlessly expand their vocabulary when reading Where the Red Fern Grows.
You can find endless, helpful lists online of great SFF books for kids. Probably the most important series to me as a child was the Chronicles of Narnia. The seven books in the series get sorted in two different orders based on publication date and the chronology of the stories themselves. I strongly recommend starting with The Lion, the Witch, and the Wardrobe. From there, either order will work.
Beyond that, I read voraciously from authors such as J.R.R. Tolkien (have you heard of him?), David Eddings, Terry Brooks, Robert Heinlein, and others. As I’ve read books along with my own children, I’ve come to love J.K. Rowling (you may have heard of her as well), Eoin Colfer, Margaret Peterson Haddix, and many more.
The goal is not to convince your child to read so that they improve their vocabulary. Rather, help them find books they love, and the process, particularly with science fiction and fantasy novels, will happen organically. Good luck!
You can check out J. Philip Horne’s books here.