Compared to other kinds of exercise, I actually do quite a lot of running. Unfortunately, this is usually when I’m late to catch a bus! To run in Welsh is rhedeg.
rhedeg
to run
Rhedeg has evolved from Middle Welsh redec, which itself is derived from the proto-Celtic *reteti. There are similar words in the other Celtic languages, like resek in Cornish and redek in Breton.
In the North, colloquially, the second syllable is sometimes pronounced quite differently:
It still tends to be spelt the same either way though – the exception might be that in a book, if most of the characters are Southern but one is Northern, rhedeg could be spelt rhedag in their dialogue to reflect their accent. It’s a bit like in English novels, where an author might use spelling changes to convey the accent of a character.
The noun form of run, as in to go on a run, is rhediad, and the plural is rhediadau. It’s a masculine noun.
There are a few other terms derived from rhedeg and rhediad, like rhedweli, which is the word for artery. It is the combination of rhedeg and gweli, which is an archaic term for a bleeding wound. Not particularly pleasant, but worth knowing about! Arteries are rhedwelïau and arterial is rhedwelïol.
Another example is rhod, which is a formal literary word for a wheel. It’s also the root of the common boys’ name Rhodri. The term used day-to-day, though, is olwyn.
Rhedeg and rhediad only respond to the soft mutation, like this:
Soft mutation
redeg
Nasal mutation
N/A
Aspirate mutation
N/A
As you can see, it’s only a slight change, with rh changing to r. Both of these sounds are rolled in Welsh, although it’s a very gentle roll, sometimes described as more like a ‘tap’ of the tongue on the roof of the mouth.
The difference between rh and r is that rh is a much softer, breathier sound – if you’re having trouble pronouncing it, try saying r in a whispering tone.
Interestingly, rhedeg is also how we say to conjugate in Welsh (although you can use ffurfdroi, too). Rhediad is also the noun form in this case, meaning a conjugation. So, let’s look at some rhediadau now!
Future | Conditional | Past | |
First person singular | Rheda(f) i I will run | Rhedwn i I would run | Rhedais i I ran |
First person plural | Rhedwn ni We will run | Rheden ni We would run | Rhedon ni We ran |
Second person singular / informal | Rhedi di You will run | Rhedet ti You would run | Rhedaist ti You ran |
Second person plural / formal | Rhedwch chi You will run | Rhedech chi You would run | Rhedoch chi You ran |
Third person singular | Rhedith o/e/hi He/she will run | Rhedai fo/fe/hi He/she would run | Rhedodd o/e/hi He/she ran |
Third person plural | Rhedan nhw They will run | Rheden nhw They would run | Rhedon nhw They wrote |
To instruct someone to run, you would say rheda (singular/informal) or rhedwch (plural/formal). Unfortunately, rhedwch reminds me of high-school P.E. classes more than anything!
Rhedon nhw adref.
They ran home.

We often use running in English to refer to things that flow, like rivers and streams. In Welsh you’d be more likely to use the literal translation of flowing, which is llifo.
However, one thing that’s the same in English and Welsh is that in both languages, noses run! If you want to say My nose is running in Welsh, you can just translate it literally and say Mae fy nhrwyn i’n rhedeg. Similarly, a runny egg can be called ŵy’n rhedeg.
Mae’r trên yn rhedeg mymryn bach yn hwyr.
The train is running a bit late.
There are plenty of reasons to take up rhedeg as a form of ymarfer corff (exercise). You might be training for a ras (race), trying to cadw’n heini (keep fit), or find that it improves your iechyd meddwl (mental health).
Whatever the reason, it’s worth investing in a good pair of esgidiau rhedeg (running shoes), or you’ll feel the impact on your pengliniau (knees) and your traed (feet). Your coesau (legs) are sure to hurt the next day if you don’t ymestyn (stretch) before your rhediad, too, and you might even get a pigyn rhedeg (a stitch). If you’re finding rhedeg too much for you and you want to arafu (slow down), you can try loncian (jogging).
Pam wyt ti’n rhedeg mor araf?
Why are you running so slowly?
Rhedeg for exercise can be fun, energising, and relaxing. In films and books, though, characters might have to rely on rhedeg in slightly less enjoyable situations, such as if they need to dianc (escape) from somewhere. In that case, they would rhedeg ymaith or rhedeg i ffwrdd (run away), and hopefully, they would rhedeg yn gyflym (run fast).
If they’re in real danger, they might even rhedeg fel cath i gythraul – this literally means run like a cat to the Devil. It just means running very fast, and is a bit like run like the Devil in English.
Another, more positive idiomatic use is rhedeg yr yrfa. It uses the word gyrfa in its soft mutated form. Gyrfa doesn’t have a direct equivalent in English, but is translated in various contexts as journey, course, or career. This phrase, then, literally means running the journey, and refers to living one’s life.