Although the Alice books are stories for children, they're probably above the reading level of children of Alice's own age (seven in Through the Looking-Glass). The introduction of longer vocabulary words and Victorian customs also adds to the difficulty for twenty-first-century readers. Still, for the most part, the books are written in simple language that most readers can understand. Most sentences are relatively short and straightforward, and when the language does become complicated, the narrator usually makes fun of it for us before it gets too heavy.
However, despite the use of simple syntax and short sentences, the style of both books is extremely clever. Plays on words, puns, homophone confusion, and metaphors becoming literal embellish and embroider Lewis Carroll's otherwise simple prose. These clever permutations of language add richness to the text and another level of enjoyment for adults or more educated readers.
In addition, both books incorporate poetic language, in the form of parodies of nursery rhymes and songs, as well as Carroll's own original nonsense poetry. The most famous poem in the Alice books is "Jabberwocky," which appears in the first chapter of Through the Looking-Glass. We've got a lot to say about "Jabberwocky" in Shmoop Poetry (and we think our critique is a bit more insightful than Humpty Dumpty's). Each novel also has a poem by Carroll as its epigraph – just take a look at the "What's Up with the Epigraph?" section.