A Quick Guide to the Joret Line
What is the Joret line? And why should I care about it?
So, to begin, a definition:
isogloss
noun /ˈaɪsəɡlɒs/ /ˈaɪsəɡlɑːs/ (linguistics)
The Oxford Advanced Learner’s Dictionary
a line on a map that separates places where a particular feature of a language is different
Named after the French historian and linguist Charles Joret, the Joret line is an isogloss that runs through northern France and Belgium (specifically through Normandy, Picardy and into Wallonia). Now, bearing in mind the inherent inaccuracy of attempts to pin down the location of linguistic features, and for the effects of French standardisation and modern social mobility, the part of the Joret line in Normandy looks so:

What does the line demarcate? It’s about sounds. Specifically, it concerns sounds that the Romance languages of the region got from Latin and Frankish, and their subsequent development. This article focuses on two sounds and their histories:
- the consonant /k/ (as in English king) when in combination with the vowel /a/
- the sound /w/ (as in water)
The former sequence, /ka/, was inherited directly from the sounds of Latin, while /w/ came from the politically prestigious newcomer to the area, Frankish. This was a Germanic language related to German and English, which arrived on the scene in the early medieval period.
In terms of these sounds, the langues d’oïl to the north of the line have been more conservative. They have more or less preserved the original sounds as they first entered the area.
In contrast, in the various dialects on the south side (including what would become Standard French), these sounds have changed. In them, the Frankish sound /w/ eventually became /g/ (as in English get). This occurred as an attempt at approximation; the languages south of Joret tried to approximate a sound that Frankish had while they did not. This mostly likely progressed in stages, at first /ɡʷ/ (like the GU in penguin) and then just /g/.
Meanwhile the consonant /k/ (when used before /a/) changed first into Old French /tʃ/ (as in English church), and then into the /ʃ/ consonant (as in shoe) that’s part of French today.
So, in sum, the changes looked like this:
Original Sound | North of Joret | South of Joret |
Latin /k/ (before /a/) | /k/ | /tʃ/, later /ʃ/ |
Frankish /w/ | /w/ | /gw/, later /g/ |
We can appreciate this better with some example words. In each of the following, we find the original consonants at the beginning of the Latin and Frankish words preserved in Norman and Picard, but transformed in Standard French.
Original Word | Norman/Picard | Modern Standard French |
Latin cantiō ‘song’ | canchon | chanson |
Latin candēla ‘candle’ | candelle | chandelle |
Latin canis ‘dog’ | quien* | chien |
Frankish *werra ‘strife’ | werre | guerre |
Frankish *wardon ‘guard’ | warder | guarder |
Okay, fine. Why should I care though?
That’s a very fair question. In short, if you know and use English, the Joret line has had a great effect on you and your language.

In 1066, the Duke of Normandy and his forces conquered England, thus starting a flood of Romance words into the English language. The language spoken by the Normans originated north of the Joret line, but the political ties with France that they established were long-lasting and not limited to its northern regions. In time, words from the languages south of Joret entered English too.
What this means is that English has taken words from both sides of the Joret line – and that many English words exist in pairs: one from the north, one from the south. When two words with a common origin but different stories exist in the same language, we call such words doublets, and when you bear in mind the features that defined the two sides of Joret, many of these doublets start to appear.
For example, English has the words car and chariot. Both descend from Latin carrus, itself a borrowing from Gaulish, but one entered English from Old Northern French, north of the Joret line, while the other underwent the /k/ > /tʃ/ change of Old French, a language south of Joret. It is also interesting that English preserves the Old French /tʃ/ sound in borrowed words like chariot, while French itself has since reduced the sound to simply /ʃ/. Carry and charge are two verbs derived from carrus that show the same correspondence.
Likewise, Latin captāre ‘to try to catch’ is the ancestor of both catch and chase, the latter of which again owes its initial /tʃ/ consonant to the phonological changes of Old French. English has also borrowed capture directly from the Latin verb, meaning that catch, chase and capture exist as triplets in English vocabulary!
In a society that with a strong dependence on livestock, it is not too surprising to learn that the original Old Northern French meaning of cattle was not ‘bovine animals’ but rather ‘personal property’. Its south-of-Joret equivalent also entered English, giving us the archaic word chattle.

Sometimes, one doublet comes into a language much later than its sister word. The Normans arguably contributed both the form and meaning of their word castel to English, giving us castle. While this is up for debate, it is clear that chateau, its countpart south of Joret, crossed the Channel much later (note its initial /ʃ/ sound, rather than /tʃ/).
It must also be said as well that the affected consonant doesn’t need to be at the beginning of the word, as pocket and pouch demonstrate.
The /w/-/g/ divide of medieval France has been just as successful in producing English doublets. For example, in modern English, a company might offer you a warranty with an assured guarantee of satisfaction. A protector can be either a guardian or a warden; you can give both your regards or a reward; and today it’s normal to store your clothes in a wardrobe, but in medieval times, you could also store them in a garderobe, a room now associated with toilets. All six of these words in fact come from a single Frankish original, *wardon.
Moreover, if you run well, a Frankish speaker might employ the compound word *walalaupan (literally *wala ‘well’ and *hlaupan ‘run’). This would also endure two fates on the two sides of Joret, the resulting words becoming English gallop and wallop. If, on the other hand, you think well, you will be using both your guile and your wiles.
To Conclude
I hope I have successfully demonstrated here what a useful etymological tool knowledge of the Joret line can be! I personally find it fascinating how it even lets us pinpoint where in France many English words come from – how the presence of a /k/ or a /tʃ/ in an English word can narrow down its place of origin pretty well.
However, the words mentioned above are only those which, thanks to the isogloss, form etymological twins in modern English; discussing the full consequences of Joret on French and English would require much more time! For the moment, let’s simply say that Joret can explain hundreds of equivalent words in the two languages, showing us why we translate English war, cauldron and William as guerre, chaudron and Guillaume. It’s handy for learners of French!
It can also, as a final point, help to reveal more obscure connections between English and French, connecting Gaul, the home of Asterix, to Wales and Wallonia – but that will have to wait until another article.