But, while puncturing the myth of a linguistic golden age, Deutscher does point us back to something akin: the Proto-Indo-European tongue, from which almost all languages from the Celtic fringe to the east of India are descended.
Through speculative archaeology, coupled with scrutiny of the linguistic past as it manifests itself in the present, he aims to show how languages evolve. Being a joker, he also gives us fun along the way. And if some of his jokes do go on a bit, he laces his story with bons mots, from Mae West's "a hard man is good to find" to Mark Twain's skit on German genders: "Hear the rain, how he pours, and the hail, how he rattles... Ah the poor fishwife, it is stuck in the mire". Genders take Deutscher into wonderful linguistic regions, like Gurr-goni in Arnhem Land, for whose speakers an aeroplane has the same gender as an edible vegetable (logically, as he shows).
The historical backbone starts with Sir William Jones's excited discovery in 1786 that Sanskrit was cognate with Latin and Greek. It proceeds via Jacob Grimm's law of sound-change explaining why - against all appearances - "hound" is cognate with "canine", "grain" with "corn", and "tooth" with "dentist". It continues with de Saussure's brilliant hypothesis on how that proto-language sounded, and continues via the vindication of this by the discovery of the cuneiform Hittite language half a century later.
There are times when Deutscher makes the brain reel (he tells us which bits can be skipped without serious loss), but others when it's nice to plod along, savouring details. Thus "resent" once meant warm approval, and "like" could work two ways, as in this exchange from The Two Gentlemen of Verona: "Host: The music likes you not? Julia: You mistake; the musician likes me not."
Deutscher is illuminating on everything, but he ends with a polemical point. It's in the threatened languages of small, preliterate societies that we should look for our linguistic beginnings.