This post is the 7th instalment of the Welsh leg of my current Celtic challenge. It covers chapter 6 of Colloquial Welsh. For earlier instalments, please see Welsh Archives – Language Miscellany
I’ve used bold type below to highlight words affected by mutations and an asterisk * to mark words followed by mutation.
Numbers
I show below Welsh numbers 1 to 100 and, for comparison, the Irish equivalents.
Table1. Numbers 1-10
| Number | Welsh | Irish |
| 1 | un, un* | aon |
| 2 | dau, dwy* | dó |
| 3 | tri, tair | trí |
| 4 | pedwar, pedair | ceathair |
| 5 | pum(p) | cúig |
| 6 | chwe(ch) | sé |
| 7 | saith | seacht |
| 8 | wyth | ocht |
| 9 | naw | naoi |
| 10 | deg | déag |
Welsh feminine forms contain dwy (instead of dau) and pedair (instead of pedwar)
The final consonants on pum(p) (5) and chwer(ch) (6) are heard only when no noun follows. Welsh numbers are generally used with a singular.
Aspirate mutation can follow tri (but not tair) and chwe, especially before c- and p-. tri cheffyl (‘3 horses’, ceffyl); tri phensil, ‘3 pencils’)
It is necessary to put a before an Irish number when:
(a) counting;
(b) giving the number of a house, flat etc; or
(c) calling out a number.
Before the 2 numbers starting with a vowel, ha is added instead of just a: a haon (1); a hocht (8).
Table 2. Numbers 11-19
| Number | Welsh (old) | Welsh (modern) | Irish |
| 11 | un ar ddeg | undeg un | aon déag |
| 12 | deuddeg | undeg dau | dó ddéag |
| 13 | tri ar ddeg | undeg tri | trí déag |
| 14 | pedwar ar ddeg | undeg pedwar | ceathair déag |
| 15 | pymtheg | undeg pump | cúig déag |
| 16 | un ar bymtheg | undeg chwech | sé déag |
| 17 | dau ar bymtheg | undeg saith | seacht déag |
| 18 | deunaw | undeg wyth | ocht déag |
| 19 | pedwar ar bymtheg | undeg naw | naoi déag |
For the numbers 11-19 (table 2), Welsh has 2 alternative counting systems. A modern decimal system uses the sequence tens-unit throughout, eg undeg (13 =one.ten 3). The modern numbers are usually followed by o* [soft mutation] plus the noun’s plural.
An old system uses the sequence units- ar* tens, but:
- 16-18 and 20 are built on the pattern pymtheg (15, mutated form bymtheg)–ar* (‘on’) unit, eg pedwar ar bymtheg (15-on-4) = 19.
- deunaw (18) is 2.9 (= 2 times 9).
- deuddag (12) lacks ar*
Irish forms the numbers from 11 -19 by adding déag (‘ten’) after the number representing the number of units. This is the same sequence as the old Welsh system, but using the decimal base throughout—and without the base 15 used in the old Welsh 15 -18 and 20 and the base in old Welsh 18. Also, Irish lacks the linking preposition ar found in the old Welsh system.
For more on the structure of numbers in Indo-European languages, please see https://languagemiscellany.com/2023/11/structure-of-numbers-in-indo-european/
Numbers 20-100
The Welsh numbers from 20 to 100 are mostly in the sequence number.deg, where deg is the base (ten) and number is the number that is multiplied by 10 to give the target (eg trideg (30) = 3.10).
There are some vestigial remains of a vigesimal (base ten) system with a basic word for 20 (ugain) that also forms the base for deugain (40 = 2.20). An alternative for 50 is hanner can(t)—’half 100’.
Table 3. Numbers 20-100
| Number | Welsh | Irish |
| 20 | ugain dauddeg | fiche |
| 30 | trideg | tríocha |
| 40 | pedwardeg deugain | daichead ceathracha |
| 50 | pumdeg hanner can(t) | caoga |
| 60 | chwedeg | seasca |
| 70 | saithdeg | seachtó |
| 80 | wythdeg | ochtó |
| 90 | nawdeg | nócha |
| 100 | can(t) | céad |
These higher numbers are followed by o* [+soft mutation] plus the noun’s plural
Welsh has both a vigesimal base system and a decimal base system throughout. For example, 40 can be either deugain (2X20) or pedwar deg (4×10); and 50 can be either deg a deugain (10+[2X20]) or pum deg (5×10).
I don’t yet have enough information to explain how the numbers between the tens (eg 35, 72) are formed, especially in Irish.
There is an International Linguistics Olympiad question on Irish numbers at https://www.uklo.org/wp-content/uploads/2022/09/2011r2.2-Irish.pdf
Welsh expressions of quantity
Faint (‘how much, how many’), llawer (‘a lot, much, many’) gormod (‘too much, too many’), digon (‘enough’), rhagor (‘more, in addition’), mwy (‘more’—interchangeable with rhagor), ychidig (‘a little, a few’), unig (‘only’)
Units of packaging: pws ‘pound (of weight, pwysig = ‘important, urgent’)), [hanner] dwsin (‘[half] a dozen’, pecyn ‘pake(et)’ tun ‘tin, potel ‘bottle’, darn a piece’, tafell (fem), a slice’, sleisen (f, a slice’), bocs (‘box’)
Expressions of quantity are followed by o* [+soft mutation]
Money
Pound is punt (fem, pl. punnoedd or punnau) and penny is ceiniog (f, pl. -au).
North Wales alternatives
Northern alternative: possession
Instalment 4 introduced the use of the verb mae with the preposition gyda (or ’da) to express possession:
(1) mae car newydd ’da John
is car new with John
‘John has a new car’
Instalment 4 is at https://languagemiscellany.com/2026/06/welsh-challenge-4/
In northern Welsh, a different construction is often used instead:
- the preposition is gan (or gyn), not gyda.
(from the vocabulary list, gan* means ‘by’) - the word order is different: the prepositional phrase gan + possessor precedes the possessed item, instead of following it.
- the possessed item undergoes soft mutation.
(2) mae gan* John car newydd
is by John car new
‘John has a new car’
(3) mae gen* i ragor o enghreifftiau fan hyn
is by me more of examples here
‘I have more examples here’
(ragor is the soft mutated form of rhagor)
Table 4 shows how gan combines with pronouns.
Table 4. Gan with personal pronouns
| gen i, gyn i | with me | gynnon ni | with us |
| gen ti, gynti | with you | gynnch chi | with you |
| gynno for | with him | gynnyn nhw | with them |
| gynni hi | With her |
Northern alternative: ‘can’
In the north, medru (‘can, be able’) often appears instead of gallu (the form mentioned in instalment 5 https://languagemiscellany.com/2026/07/welsh-challenge-5/).
It works roughly the same way, eg fedri di (‘can you?’, note mutation), fedrech chi* (‘could you’).
Esiau ‘want, angen ‘need’
Esiau ‘want’ and Angen ‘need’ are nouns. They combine with bod (‘be’) to form verb phrases. Unlike phrases consisting of bod and a verbal noun, they do not contain yn.
(4) Mae Roy a Stella angen petrol
Are Roy and Stella need petrol
Roy and Stella need petrol.’
Compare with:
Mae Roy a Stella’n gyrru Jeep
‘Roy and Stella need a Jeep’
Dych chi esiau i mi* … [+ verbal noun] (‘do you want me to …’)
oes angen … arnoch chi? (‘do you need … ?’)
Both esiau and angen can be used in impersonal constructions using mae (interrogative oes, negative (doe)s dim) to express ‘there is a need’ etc.
(5) mae angen mwy o *gefnogaeth
is need more of support
‘more support is needed’
’sdim eisiau poeni ‘there’s no need to worry about that’
oes angen dweud rhywbeth ‘should something be said?’
eisiau is pronounced isio (N), ise (Mid) or isie, but never as spelt.
Another way to say want is am* + verbal noun
maen nhw am ddysgu ‘they want to learn’
Another word for ‘want’
Many southern areas use a verbal noun moyn or mofyn for ‘want’, and unlike the construction with eisiau (example 6) this does need the linking yn (example 7)
(6) Dyn ni eisiau mynd adre
‘we want to go home’
(7) Dyn ni’n moyn mynd adre
‘we want to go home’
In some areas, moyn can mean‘fetch’:
Cer i moyn y llaeth, nei di? ‘go and fetch the milk, will you?
Moyn does not undergo mutation here.
Demonstratives
Hyn ‘this, hynny ‘that’
Some idioms: ar hyn o *bryd ‘at the moment’, hyd yn hyn ‘up to now’ [also hyd yma], hy noll ‘all this’, fel hyn ‘like this, in this way’, fel hynny, fel ’ny ‘like that’ *bryd hynny / *bryd ’ny ‘at that time’, wedi ’ni ‘after that’, ‘then’
Prepositions
Soft mutation after prepositions
Most prepositions, including those shown in table 5, trigger soft mutation.
Table 5. Some prepositions, all causing soft mutation*
| Preposition | Meaning | Preposition | Meaning |
| am* | [various] | hyd* | up to, as far as |
| ar* | on | i* | to, for |
| at* | at, to | o* | from, of |
| (o) dan* | under | tan* | until |
| dros* | over; for | trwy* (dywy* ) | through |
| gan* | by; with | wrth* | [various] |
| heb* | without |
Am* and wrth* both have several meanings.
Some of the prepositions have special meanings when used with verbal nouns, eg
- Dychi chi am *dalu â siec?
Do you want to pay by cheque? - Mae’r bws ar *fynd?
The bus is about to go. - Mae Elspeth a Linda heb *ddod.
Elspeth and Linda have not come. - Canwch y larwm drywy *dorri’r gwydr
Sound the alarm by breaking the glass. - Dwy i’n mynd i* …
I’m going to …
The prepositions mewn and yn (‘in’)
The preposition meaning ‘in’ is:
- yn [followed by nasal mutation] before specifically defined nouns:
– a word preceded by the definite article (y etc) or by a possessive pronoun. See instalment 5 for possessive pronouns https://languagemiscellany.com/2026/07/welsh-challenge-5/
– a pronoun
– the name of a person or place - mewn in all other cases. Mewn doesn’t trigger mutation.
Prepositions before genitive noun phrases
If a mutation-inducing preposition precedes a noun preceded by a definite article, the article blocks mutation. But, in possessive phrases, no definite article precedes the possessed item, so mutation is not blocked:
ar* y copa (‘on the summit’)
ar* gopa y mynydd (‘on [the] summit of the mountain)
Words and phrases
Shopping
torth ‘loaf’, bara ‘bread’ menyn ‘butter’, caws ‘cheese’, bresych ‘cabbage’, tatws ‘potatoes, moron ‘caarots’ letys ‘lettue’, ffa ‘beans’, ffa pob ‘baked beans’, ffa dringo ‘runner beans’, sgewnyll ‘spouts’, uwd ‘porridge’, creision ŷd ‘cornflakes’, melysion ‘sewwts’, orennau ‘oranges’, fala ‘apples pl -ua, bananas ‘bananas’, pysgod ‘fish’
Llaeth ‘milk’, cig moch ‘pork’, cig eidion ‘beef’, cig lâr ‘chicken, ‘, selsig ‘suasages(), bisgedi ‘biscuits’, halen ‘salt, pupur ‘pepper’, sebon ‘soap’powder golchi ‘washing powder’
Other words and phrases
Nouns: raglan ‘programme’, furflen ‘form’, llyfr (‘book’ plural -au), bachgen ‘boy’, merch ‘girl’ ymwelwyr ‘visitors, clorian ‘scales [fem] mis ‘momth’, awyr ‘air’, cyfrir ‘account’, cyfredol (‘current’), cyffriadu (-on) computer, credyd (‘slip, form’), ysgol ‘school’ (-pl. -iol)
Verbs cael ‘get’, danfon ‘send’, trosglwyddo ‘transfer’, cadw ‘keep, depoist’, arwyddo (sign)
Adjectives *trwm ‘heavy’, anodd ‘difficult’, peryglus (‘dangerous, perilous’), cynta (‘first’)
Adverbs; fel arall ‘otherwise’, gyda’i gilydd ‘together’, pryd (‘when’)
Places yr Unol Daleithiau (‘the Uniterd States’)
Conjunctions and pronouns; os (‘if’) popeth (‘evryting’)
Phrases:
rhy ddrud (‘to expensive)
Oes … ar ôl ’da chi? (do you have any … left?’)
Prydd bydd rhagor ’da chi? (‘when will you have (some) more (in)?)
Rhowch* … i mi (‘give me …’)
allech chi roi’r cyfan mewn bocs i mi? (‘ Could you put it all in a box for me?’)
Does gen i ddim newid / llai (N); does dim newid / llai ’da fi (S) I’ haven’t got any change / anything smaller.
Tra bo fi ’ma (‘I’d better’)
faint gymerith e? (‘how long will it take?’)
neu *beidio? (‘or not’, peido – ‘stop, don’t’)
ail ddosbarth (‘2nd class’)
mae ofn arna i (I’m afraid’)
dim ots (‘it doesn’t matter’)
na i* …. (‘I’ll …’)
Source
Colloquial Welsh, Gareth King (2008)