Editing Dual (grammatical number) (section)

===Celtic languages===
Reconstructed [[Proto-Celtic]] nominal and adjectival declensions contain distinct dual forms; pronouns and verbs do not. In [[Old Irish]], nouns and the definite article still have dual forms, but only when accompanied by the numeral ''{{lang|cel-x-proto|da}}'' "two". Traces of the dual remain in [[Middle Welsh]], in nouns denoting pairs of body parts that incorporate the numeral two: e.g. {{lang|wlm|deulin}} (from {{lang|wlm|glin}} "knee"), {{lang|wlm|dwyglust}} (from {{lang|wlm|clust}} "ear").<ref>{{cite book |last=Lewis |first=Henry |author2=Holger Pedersen |title=A Concise Comparative Celtic Grammar |location=Göttingen |publisher=Vandenhoeck & Ruprecht |year=1989 |edition=3rd |pages=§§246, 468 |isbn=3-525-26102-0 }} {{cite book |last=Thurneysen |first=Rudolf |title=A Grammar of Old Irish |others=Trans. by [[D. A. Binchy]] and [[Osborn Bergin]] |publisher=Dublin Institute for Advanced Studies |year=1993 |orig-date=1946 |isbn=1-85500-161-6}} {{cite book |last=Evans |first=D. Simon |title=A Grammar of Middle Welsh |publisher=Dublin Institute for Advanced Studies |year=1989 |orig-date=1964 |pages=§§30, 33 |isbn=1-85500-000-8}}</ref>

In the modern languages, there are still significant remnants of dual number in [[Irish language|Irish]] and [[Scottish Gaelic]] in nominal phrases containing the numeral {{lang|ga|dhá}} or {{lang|gd|dà}} (including the higher numerals 12, 22, etc.). As the following table shows, {{lang|ga|dhá}} and {{lang|gd|dà}} combines with a singular noun, which is [[lenition|lenited]]. Masculine nouns take no special inflection, but feminine nouns have a [[Palatalization (phonetics)|slenderized]] dual form, which is in fact identical to the dative singular.<ref>{{cite book |last=Ó Maolalaigh |first=Roibeard |author2=Iain MacAonghuis |title=Scottish Gaelic in Three Months |publisher=Hugo's Language Books |year=1997 |isbn=978-0-85285-234-7}}</ref>

{| class="wikitable"
! Singular || Dual || Plural
|-
| {{lang|ga|lámh}} ("a hand" in Irish)
| {{lang|ga|dhá láimh}} ("two hands")
| {{lang|ga|trí lámh}} ("three hands")
|-
| {{lang|gd|clach}} ("a stone" in Scottish Gaelic)
| {{lang|gd|dà chloich}} ("two stones")
| {{lang|gd|trì clachan}} ("three stones")
|}

Languages of the [[Brythonic languages|Brythonic]] branch do not have dual number. As mentioned above for Middle Welsh, some nouns can be said to have dual forms, prefixed with a form of the numeral "two" (Breton {{lang|br|daou- / div-}}, Welsh {{lang|cy|dau- / deu- / dwy-}}, Cornish {{lang|kw|dew- / diw-}}). This process is not fully productive, however, and the prefixed forms are semantically restricted. For example, Breton {{lang|br|daouarn}} (< {{lang|br|dorn}} "hand") can only refer to one person's pair of hands, not any two hands from two different people. Welsh {{lang|cy|deufis}} must refer to a period of two consecutive months, whereas {{lang|cy|dau fis}} can be any two months (compare "fortnight" in English as opposed to "two weeks" or "14 days"; the first must, but the second and third need not, be a single consecutive period).<ref>{{cite journal |last=Heinecke |first=Johannes |title=Is there a Category of Dual in Breton or Welsh? |journal=Journal of Celtic Linguistics |volume=7 |year=2002 |pages=85–101 }}</ref>
The modern Welsh term {{lang|cy|dwylo}} (= hands) is formed by adding the feminine (and conjoining) form of 'two' ({{lang|cy|dwy}}) with the word for 'hand' — {{lang|cy|llaw}} becoming {{lang|cy|lo}} as it is no longer in a stressed syllable.