Henry Hitchings's book is aptly titled. Words do have a secret life, or rather a secret past. George Steiner, quoted here, put it well: "When using a word we wake into resonance ... its entire previous history." In the case of English, that's a lot of history to explore: even by the most conservative estimate there are 700,000 words in our current lexicon.

English also became English through fundamental changes in grammar and pronunciation, but Hitchings is only concerned with vocabulary. That could have resulted in a book that was just an extended footnote to the OED's compressed etymologies, and it is hard to imagine this book being written without the digital version of the great dictionary which makes it possible, for instance, to find instantly all of the English words taken from Basque (since you ask, "anchovy" and "basque"). But etymology is just Hitchings's starting point; he shows us that the history of our vocabulary is the history of our place in the world

The book has a broad chronological sweep, from pre-Roman Britain to the latest street slang, but individual chapters tend to work through particular cultural encounters or themes, sometimes with extended digressions. A chapter called "Powwow" is a masterly focused account of our early exploration of America and our encounters with its languages. A chapter called "Connoisseur" manages to encompass not only the 18th century's extensive borrowings from French, but also the era's vogue for grammar books and dictionaries, the rise of scientific writing, the use of Italian terms in music, and the lexicon of travel and exploration, including an account of our first confrontations with Australian aboriginal languages.

Download the new Independent Premium app Sharing the full story, not just the headlines

We talk about "borrowing" words. It's a shorthand way of describing a complex process. Hitchings uses it, just as he talks about writers "coining" words when he really means that their earliest printed appearance so far unearthed is in their works. But he also gives an intelligent account of what really happens when two languages come into contact. There is an exchange of terms; but the breadth and depth of that exchange is dependent upon the strength of the relationship. And it is not just about us learning their language: they need to learn ours, bringing their words – their nouns, principally – with them.

That helps explain the huge differences in the extent to which borrowing took place. We have taken more words from French than anywhere else, because theirs is a culture with which we have been intimately engaged for 1,000 years. But we also took a surprising amount from native American languages, because we settled there and – at the beginning – enjoyed fruitful relationships with them. In contrast, we took next to nothing from aboriginal Australian languages.

Is English inherently a "promiscuous" language, especially willing to take part in these exchanges? Hitchings thinks not. The extent of its borrowings has more to do with the political realities of England's (and later Britain's) involvement with the world. On the other hand, the shift away from an Old English grammar based upon inflectional word-endings to one based on word order has made it easy for words to be accommodated; most new words come from adaptations of existing terms, rather than borrowing.

One of the themes of the book is the recurring tension between those who want the language to be pure, simple and Germanic and those who relish promiscuity, complexity, and the new. Hitchings points out that words only come into the language because there is a need for them, and finds a few harsh – and funny – words for those purists who have, over the centuries, fought battles over individual words. At the same time, he concedes that "there are compelling reasons for ... wanting a large degree of stability in our language".

The only serious argument I have is with Hitchings' conventional account of the Anglo-Saxon invasion of "Celtic" south and east Britain. Only a tiny clutch of nouns and a few more placenames survived, suggesting a kind of linguistic Year Zero. But by his own account, no such cleansing has taken place elsewhere in the world, even where there were actual genocides. I have been persuaded by the alternative explanation, put forward in Stephen Oppenheimer's The Origins of the British, that the pre- and post-Roman inhabitants of England spoke a Germanic language that was seamlessly incorporated into Old English.

But Hitchings is far more informed on these matters than I am. His bibliography runs to 27 pages, and the book is admirably footnoted and indexed. The scholarship, though, is unobtrusive. Even in the denser sections, this clever, persuasive, delightful book is studded with entertaining observations, whether he's telling us that "poppycock" comes from the Dutch for "doll's shit", or that the Australian language Guugu Yimidhirr has a special vocabulary reserved for talking to one's brother-in-law.