Consider Carroll’s use of (invented) words in this stanza. What are ‘toves’, and why are they ‘slithy’? What does ‘slithiness’ (is that a word?) look or feel like? The same with ‘mimsy’. Noam Chomsky’s ground-breaking work in linguisticssurrounding children’s ability to acquire a linguistic ‘grammar’ demonstrated that even if we don’t know the meaning of a word, we can often deduce what kind of word it is: i.e. we know ‘mimsy’ is an adjective, or describing-word, even though we don’t fully know what ‘mimsiness’ is.Carroll is using both ‘slithy’ and ‘mimsy’ as portmanteau words: slithy, for example, is a blend of slimy + lithe, while mimsy suggests miserable + flimsy. Another term for a portmanteau word is, in fact, a blend, and some linguists prefer to use the word blend. But the term ‘portmanteau’ came about because, after Alice has encountered the poem ‘Jabberwocky’ in Through the Looking-Glass, and puzzled over the meaning of these unfamiliar words, she meets Humpty Dumpty, who tells her, when she quotes the above stanza:‘That’s enough to begin with,’ Humpty Dumpty interrupted: ‘there are plenty of hard words there. “Brillig” means four o’clock in the afternoon — the time when you begin broiling things for dinner.’‘That’ll do very well,’ said Alice: ‘and “slithy”?’‘Well, “slithy” means “lithe and slimy”. “Lithe” is the same as “active”. You see it’s like a portmanteau — there are two meanings packed up into one word.’A portmanteau was, in Victorian times, a case or bag for carrying clothing while travelling; the word is from the French meaning literally ‘carry the cloak’.So, as well as being a fine piece of imaginative literature, ‘Jabberwocky’ also demonstrates a central principle of language: what linguists call productivityor open-endedness, namely the phenomenon whereby users of a language can endlessly create new words or phrases. As Noam Chomsky’s theory of a Universal Grammar shows, users of a language demonstrate an innate linguistic creativity from a young age, and this is how children are able to pick up a new language relatively quickly: they learn not simply by acquiring knowledge, but by using an in-built talent for spotting how words are put together to form meaningful utterances. If something is both lithe and slimy, why not combine the two words – both their sounds and their meanings – to create slithy?