Not exactly The Da Vinci Code-but the first ever Breton-Welsh dictionary might sell, um, a few.
It's certainly catering for a niche market, but a matchbox-sized dictionary has been created for Welsh speakers holidaying in Brittany. There are similarities between Welsh and Breton, including many words which sound almost identical. And with direct flights now available from Cardiff Airport to Lorient, Brittany, the new Breton-Welsh dictionary, compiled by Aberystwyth academic Rhisiart Hincks, might be a useful holiday companion. But there's a catch. If you walk into a shop in Brittany and ask for 'bara' for bread, the chances are you'll be met with blank stares unless you ask for 'pain' instead.
The language has declined so much that practising your Breton phrases could require travelling to remote rural villages or farmsteads.
'Breton is in a weaker situation than Welsh,' said Dr Hincks, senior lecturer in Welsh and Breton at the University of Wales, Aberystwyth.
'If you go to rural areas, to the very small villages or farmhouses in the west, people aged over 50 usually will be able to speak some Breton, perhaps quite a bit of it.
'But by now the language is weak. It's possible to get hold of Breton speakers anywhere, but the language is not very obvious.'
He was asked to compile the new dictionary by Breton publisher Yoran Delacour, who has already produced Breton dictionaries for speakers of other languages, and even a Cornish- English dictionary.
Although the Breton-Welsh dictionary measures just 6.3cm by 4.7cm, it contains 8,000 words.
Dr Hincks translated the same words as were used for previous dictionaries by the Yoran Embanner imprint, adding a few key words like 'eisteddfod' and 'noson lawen' - equivalent of Brittany's fest-noz.
He said Welsh speakers had a head start in learning Breton, but would still have to put in many hours of study before being able to converse in or read the language.
'Hearing someone speak Breton is totally foreign, but when you see it written down it's not that different from Welsh really,' said Dr Hincks, speaking from the Basque area of France where he is on a course to learn the Basque language.
'Breton is harder to learn than you'd expect, but that's true of any language.
'Learning enough to say 'The weather is nice' is easy in Breton, as in any language, but being able to converse or read books involves quite a lot of hard work.'
Although it's unlikely to rival the Da Vinci Code for sales, Yoran Delacour said he expected some Bretons to buy the new dictionary out of curiosity.
'People in Brittany will buy it to compare the two languages, because they are very close to each other. It's not a problem for us to pronounce Welsh words, except the ll - which is a bit difficult.'
He is now planning a pocket Welsh- French dictionary, with pages twice the surface area of the new Welsh-Breton one.
He said he had sold about 500 matchbox-sized dictionaries in Brittany, where they were displayed on wooden stands in shops. The most popular was Breton-French, followed by Breton-English. Breton dictionaries for eight languages were available.
His bestseller, however, was the Cornish-English dictionary, which tourists had snapped up in Cornwall.
'Last summer 5,000 copies were sold and we will print 8,000 more at the end of this month. 'I am pleased with this, because it's a good collaboration between two peoples who are next to each other. The Cornish language is closer to Breton than Welsh is to Breton.' Geiriadurig Brezhoneg/Kembraeg (Geiriadur Bach Cymraeg/Llydaweg) by Yoran Embanner of Fouesnant, Brittany, at pounds 4. Available in some Welsh bookshops distributed by Welsh Books Council.: Breton quiz:What do the following Breton words mean? If you can speak Welsh, you should score better than someone who knows no Welsh, but beware of false friends! 1) Gloan 2) Digwener 3) Dimezell 4) Pemzek 5) Hanter-kant 6) Askorn 7) Kleze 8) Ar 9) Politikel 10) Konikl 11) Tas 12) Skinwel 13) Hon 14) Moualc'h 15) Hollved ANSWERS (IN ENGLISH AND WELSH) 1) Wool (gwlen) 2) Friday (dydd Gwener) 3) Young lady/Miss (boneddiges/merch ddibriod) 4) Fifteen (pymtheg) 5) Fifty (hanner cant) 6) Bone (asgwrn) 7) Sword (cleddyf) 8) The (y/yr) 9) Political (gwleidyddol) 10) Rabbit (cwningen) 11) Cup (cwpan) 12) Television (teledu) 13) Our (ein) 14) Blackbird (mwyalchen) 15) Universe (bydysawd/hollfyd)