I've read this before: it's the kind of book you can read a number of times without its freshness ever leaving you. It's a sort of fairy story for adults.
The narrator is the ten-year-old Jeanne – think of Joan of Arc, she boasts – who has a fourteen-year-old brother Thomas, and their parents are divorced. They're used to travelling by ship to see their parents when school's out, but this time there's a shipwreck and they are the only survivors. They spend a brief time on a small island until their parents come and collect them. But it's what they see on the island that is important.
La Grammaire est une chanson douce is strong on social criticism: in the first chapter we see Jeanne and her class friends being taught by Mademoiselle Laurencin, a woman in love with literature and words in general who has to be sent to have her enthusiasm ironed out and a more 'scientific' approach instilled. On the island the children – who have both lost their voices in the wreck – learn of the politician Nécrole, who sometimes burns down libraries to the delight of 'business men, bankers and economists': limiting vocabulary makes sound business sense.
Jeanne and Thomas are shown around the island by Monsieur Henri, who is a creation inspired by the guitar-playing wordsmith Henri Salvador (1917–2008). Monsieur Henri teaches them to find their voices again, and tells them that without language things – life itself – will die. On the island there's a shop, for instance, where customers can buy words to express their love for someone: saying 'I love you' is not enough, it's a hackneyed expression that becomes tired and wears out through overuse. Words are seen as living organisms that form relationships with other words, which bond, even marry. A very old and very respected woman breathes life into archaic words to revive them.
A sheer joy to read.
(I note that the English translator couldn't decide whether 'douce' means 'gentle' or 'sweet' here, so in the end kept both words: I don't know what the rest of the translation reads like, but the title is in the spirit of the book itself!)