This is an interesting question! "Jabberwocky" is, after all, a famously nonsensical poem: many of the words in it are not real words at all. At the same time, however, it is generally clear to the reader what (vaguely speaking) is intended. The tone of the poem is triumphant and upbeat, as is communicated by the multiplicity of exclamation points and the use of joyful language such as "Callooh! Callay!" by the boy who ventures out to slay the fearsome Jabberwock.

We as readers aren't entirely sure what the Jabberwock is, but we know that the boy's father is filled with "joy" at his son's defeat of it, and we, to an extent, share that joy. The joyful mood of the poem is fostered by its simple structure: a basic ABCB rhyme scheme and a regular rhythm which makes the poem easy to recite and remember.

The first stanza and the last one are identical, which also creates a sense of calm towards the end of the poem: the Jabberwock has been slain, and now the world can return to what it was before. This poem is often included in anthologies for children, and the calming final stanza after the outburst of joy makes it particularly suitable for this and pleasant to read aloud.