Welsh Language - Counting System

Counting System

The traditional counting system used by the Welsh language is vigesimal, which is to say it is based on twenties, as in standard French numbers 70 (soixante-dix, literally "sixty-ten") to 99 (quatre-vingt-dix-neuf, literally "four twenties nineteen"). Welsh numbers from 11 to 14 are "x on ten", 16 to 19 are "x on fifteen" (though 18 is deunaw "two nines"); numbers from 21 to 39 are "1–19 on twenty", 40 is "two twenties", 60 is "three twenties", etc. This form continues to be used, especially by older people, and it is obligatory in certain circumstances (such as telling the time).

There is also a decimal counting system, which has become relatively widely used, though less so in giving the time, ages, and dates (it features no ordinal numbers). This system is in especially common use in schools due to its simplicity, and in Patagonian Welsh. Whereas 39 in the vigesimal system would be pedwar ar bymtheg ar hugain ("four on fifteen on twenty"), in the decimal system it would be tri deg naw ("three tens nine").

While there is only one word for "one" (un), it triggers the soft mutation (treiglad meddal) of feminine nouns, other than those beginning with "ll" and "rh". There are separate masculine and feminine forms of the numbers "two" (dau and dwy), "three" (tri and tair) and "four" (pedwar and pedair), which must agree with the grammatical gender of the objects being counted.