You’d think the world was a complicated enough place, without people going around making up more languages; but we’ve been at it since the Tower of Babel went out to tender, and according to this intriguing book of essays – which addresses everything from Polari to Gargish – there have been more than 1,000 such inventions.

As Michael Adams explains, his subject covers a colourful spectrum. Some of the languages are mere curiosities of lexifabricography, whereas others are responses to perceived cultural shortcomings. Into this latter category fall the International Auxiliary Languages (IAL), schemes that were supposed to be successors to the various languages of empire. Neither Volapük – which in 1888 boasted two million students – nor the more famous Esperanto managed to be truly universal, but they were taken seriously, despite the squabbling and factionalism that seems to attend such enterprises. The Soviet Union inscribed some of its postage stamps with Esperanto, and Hitler identified it as part of the Jewish bid for global dominion. The offspring tongues Hom-Idyomo and Novial were rather less influential.

Another phenomenon involves artificially ‘revitalised’ languages, such as Cornish, Irish, and Hawaiian. Perhaps the most notorious of these examples of systematic ‘language planning’ might be