The Welsh Number SystemEdit

Welsh, being a Celtic language, traditionally used the base 20 (vigesimal) system. This system is common among adults, but not so common among children (who now use the newer base 10 system).

Vigesimal SystemEdit

Using a base of 20 means that numbers start counting again when you reach 20 instead of the modern (and common) 10. A few vestiges of this type of system exist in English (e.g Abraham Lincoln's Gettysburg Address: Four score and seven years ago...) as well as in other languages (French 80 quatre-vingts, lit. four twenties)

The numbers (1-20):

1 Un 11 Unarddeg
2 Dau 12 Deuddeg
3 Tri 13 Tri ar ddeg
4 Pedwar 14 Pedwar ar ddeg
5 Pump 15 Pymtheg
6 Chwech 16 Un ar bymtheg
7 Saith 17 Dau ar bymtheg
8 Wyth 18 Deunaw
9 Naw 19 Pedwar ar bymtheg
10 Deg 20 Ugain

(Note deunaw literally means "two nines" - 18)

From this point, we count the same, only adding ar hugain (on twenty) at the end

21 Un ar hugain
22 Dau ar hugain
23 Tri ar hugain
24 Pedwar ar hugain
25 Pump ar hugain
26 Chwech ar hugain
27 Saith ar hugain
28 Wyth ar hugain
29 Naw ar hugain
30 Deg ar hugain
31 Unarddeg ar hugain
32 Deuddeg ar hugain
33 Tri ar ddeg ar hugain
34 Pedwar ar ddeg ar hugain
35 Pymtheg ar hugain
36 Un ar bymtheg ar hugain
37 Dau ar bymtheg ar hugain
38 Deunaw ar hugain
39 Pedwar ar bymtheg ar hugain
40 Deugain

- This system repeats itself until 60 (note, 50 on its own is often called Hanner cant - half a hundred), and on again until 80

  • Trigain - 60
  • Pedwar Ugain - 80

When we get to 100, we use cant. This time, we use cant a/ac, thus:

  • Cant ac un - 101
  • Cant ac un ar hugain - 121 (literally One hundred and one on twenty)

Further numbersEdit

  • Mil - 1000
  • Deg Mil - 10,000
  • Can Mil - 100,000
  • Miliwn - 1 Million
  • Biliwn - 1 Billion

Decimal SystemEdit

As Welsh language education took off, the difficulties of using a base 20 number when trying to teach children maths became apparent (three score and eleven minus three, anyone?), so a decimal system in common with other Indo-European languages was set up to make the teaching in Welsh simpler. This system has become common among the younger generation, in the same way the metric system has taken hold in the UK as a whole. The decimal system is very simply sum-of-parts: 34 is "three 10 four" tri deg pedwar, 20 is "two 10" dau ddeg.