“What is your favourite dialect word?”

This was a question that I should really have anticipated, but it took me by surprise. I had just talked to a packed marquee at the 2018 Hay Festival about why dialects of English are of such enduring interest to the language’s speakers.

“Cwtch,” I lied.

To be honest, as a south Walian living in south Wales, I am approaching the point where I will have had a gutful of the word cwtch. The Welsh-English word, meaning a “hug” or “cuddle”, is everywhere. You can find it on mugs, cushions, greetings cards, ornaments, t-shirts, and even in the names of cafes and festivals. But that’s why, trying to keep cool in my desperation, I chose cwtch – or “cwtsh”.

One thing I like about dialect words is that you can’t always rely on them to have a consistent spelling, because they are dialect words, not Standard English words. By definition, Standard English words’ spellings have been standardised down the centuries, while dialect words have not been subject to the same pressures.

Dialect words are local, regional words and cwtch is particularly associated with the Welsh-English dialect of south Wales. It has become something of a local symbol, a symbol of local-ness and a symbol of Welsh-English-ness – especially because it is perceived as having been borrowed into south Wales English from the Welsh language.

But there is more to cwtch than this. It can be a noun or a verb. It can also mean a small storage place used for food or odds and ends, or used as a hiding place, or it can mean to squat down or crouch. The Oxford English Dictionary (OED) dates its earliest use in English to the late 19th century, but its history goes back further than that. And, on looking into it, one can find a wonderful example of why dialects are a fascinating characteristic of language.

The OED has not always been interested in dialect words. These were once only to be found in their own dictionaries and glossaries. The earliest dialect dictionary of English on a national scale was John Ray’s Collection of English Words Not Generally Used, published in 1674. The biggest and best known of these great scholarly works is Joseph Wright’s six-volume English Dialect Dictionary, published between 1898 and 1905. As its title page puts it, it was “the complete vocabulary of all dialect words still in use, or known to have been in use during the last two hundred years”.

Wright recorded the dialect word “couch”, meaning “to lie down or crouch”, in use in many parts of England and Scotland, including the west of England, at the time. It is likely that cwtch is a Welshing of couch, which itself was a medieval adoption of French “coucher”, ultimately coming from Latin “collocāre” – “to lay in its place, lay aright, lodge”. So it turns out that this seemingly most local word has quite an international story, travelling from Latin down into French across into English then Welsh and then back into English.

It’s a good example, cwtch. It shows us that even the most socially symbolic local words can have an international ancestry and the same can be said of dialects and of languages in general. We think of them as distinct and unique entities, but they connect up like the branches of a tree. In fact, the notion of a family tree is a metaphor that has framed the study of dialects, languages and their features for the last two centuries.

In 1786, the Welsh philologist William Jones put forward the hypothesis that many of the languages of Europe and Asia belong to the same family, originating in one source language, which scholars named Proto-Indo-European. It is thought that Proto-Indo-European was a collection of associated dialects spoken about 7,000 years ago in the region to the northwest of the Caspian Sea.

In the following millennia, according to the most accepted theory, the Indo-Europeans migrated in a sequence of waves westwards and eastwards, taking with them their dialects, which over time transmuted into separate languages, consisting of their own dialects, which also diversified into separate languages, and so on. Eventually, some of these migrants even reached the British Isles, giving us the beginnings of (most of) the Celtic languages and, a little later, English – though it took a few centuries of Anglo-Saxon settlement in Britain for these Germanic dialects to acquire the collective name “Englisc”.

Linguistic history is intimately and undeniably bound up with diversity and population movement, whether we focus on an individual word or a dialect or a language. Several centuries of work by dialect scholars has made this basic point clear. Though cwtch may be the Welsh-English word of the moment, as Wales, the UK and the rest of the world changes who knows how far it will travel in the future?