Editing Welsh language (section)

==Counting system==
{{Main|Welsh numerals}}
The traditional counting system used in the Welsh language is [[vigesimal]], i.e. it is based on twenties. Welsh numbers from 11 to 14 are "''x'' on ten" (e.g. {{lang|cy|un ar ddeg}}: 11), 16 to 19 are "''x'' on fifteen" (e.g. {{lang|cy|un ar bymtheg}}: 16), though 18 is {{lang|cy|deunaw}}, "two nines"; numbers from 21 to 39 are "1–19 on twenty"(e.g. {{lang|cy|deg ar hugain}}: 30), 40 is {{lang|cy|deugain}} "two twenties", 60 is {{lang|cy|trigain}} "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, and in ordinal numbers).<ref>King, G. ''Modern Welsh: A Comprehensive Grammar'', published by Routledge, {{ISBN|0-415-09269-8}} p. 114</ref>

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 originated in Patagonian Welsh and was subsequently introduced to Wales in the 1940s.<ref>{{Cite book |url=https://books.google.com/books?id=ackmDAAAQBAJ&pg=PT112 |title=Count Us In: How to Make Maths Real for All of Us |last=Robert's |first=Gareth Ffowc |date=2016-02-15 |publisher=University of Wales Press |isbn=978-1-78316-798-2 |language=en}}</ref> Whereas 39 in the vigesimal system is {{lang|cy|pedwar ar bymtheg ar hugain}} ('four on fifteen on twenty') or even {{lang|cy|deugain namyn un}} ('two twenty minus one'), in the decimal system it is {{lang|cy|tri deg naw}} ('three tens nine').

Although there is only one word for "one" ({{lang|cy|un}}), it triggers the [[Welsh morphology|soft mutation]] ({{lang|cy|treiglad meddal}}) of feminine nouns, where possible, other than those beginning with "ll" or "rh". There are separate masculine and feminine forms of the numbers 'two' ({{lang|cy|dau}} and {{lang|cy|dwy}}), 'three' ({{lang|cy|tri}} and {{lang|cy|tair}}) and 'four' ({{lang|cy|pedwar}} and {{lang|cy|pedair}}), which must [[Agreement (linguistics)|agree]] with the [[grammatical gender]] of the objects being counted. The objects being counted appear in the singular, not plural form.