'Dual' is a
grammatical number that some languages use in addition to singular and
plural. When a noun or pronoun appears in dual form, it is interpreted as referring to precisely two of the entities (objects or persons) identified by the noun or pronoun. Verbs can also have dual agreement forms in these languages.
Comparative characteristics
Many languages make a distinction between singular and
plural: English, for example, distinguishes between ''man'' and ''men'', or ''house'' and ''houses''. In some
languages, in addition to such singular and plural forms, there is also a 'dual' form, which is used when exactly two people or things are meant. In many languages with dual forms, use of the dual is mandatory, and the plural is used only for groups greater than two. However, use of the dual is optional in some languages such as many modern Arabic dialects including
Egyptian Arabic. In other languages such as
Hebrew, the dual exists only for a few measure words and for words that naturally come in pairs, such as eyes. In
Slovene, strangely, the dual is used for most nouns, but ''not'' for nouns that come in natural pairs; the plural is used instead.
Although relatively few languages have the dual number and most have no number or only singular and plural, using different words for groups of two and groups greater than two is not uncommon.
English has words distinguishing dual vs. plural number, including: ''both/all'', ''between/among'', ''latter/last'', ''either/any'', and ''neither/none''.
Japanese, which has no grammatical number, also has words ''dochira'' (which of the two) and ''dore'' (which of the three or more), etc.
Use in modern languages
Among living languages,
Modern Standard Arabic has a mandatory dual number, marked on nouns, verbs, adjectives and pronouns. (First-person dual forms, however, do not exist; compare this to the lack of third-person dual forms in the old Germanic languages.) Many of the spoken Arabic dialects have a dual marking for nouns (only), but its use is not mandatory. Likewise,
Akkadian had a dual number, though its use was confined to standard phrases like "two hands", "two eyes", and "two arms".
The
Inuktitut language uses dual forms; however, the related
Greenlandic language does not.
Austronesian languages, particularly
Polynesian languages such as
Hawaiian,
Niuean and
Tongan, possess a dual number for pronouns but not for nouns (indeed, they tend not to mark nouns for number at all). Other Austronesian languages, particularly those spoken in the
Philippines, have a dual first-person pronoun; these languages include
Ilokano (''data''),
Tausug (''kita''), and
Kapampangan (''ikata''). These forms mean ''we'', but specifically ''you and I''. This form once existed in
Tagalog but has largely disappeared, save for certain rural dialects, since the middle of the 20th century.
The dual was a standard feature of the
Proto-Uralic language, and lives on in
Sami languages and
Samoyedic languages, while other branches like Finnish, Estonian and Hungarian have lost it. Sami also features dual pronouns, expressing the concept of "we two here" as contrasted to "we". Nenets, a Samoyedic language, features a complete set of dual
possessive suffixes for two systems, the number of possessor and the number of possessed objects (for example, "two houses of us two" expressed in one word).
The dual form is also used in several modern Indo-European languages, such as
Scottish Gaelic,
Slovene and
Sorbian (see below for details). The dual was a common feature of all early Slavic languages at the beginning of the second millennium.
Hebrew
Biblical and Mishnaic Hebrew
In
Biblical,
Mishnaic, and
Medieval Hebrew, like
Arabic and other
Semitic Languages, all nouns can have singular, plural or dual forms
[1] However, in practice, most nouns use only singular and plural forms. Usually ים is added to
masculine words to make them plural for example ''ספר/ספרים'' "book/books", whilst with
feminine nouns the ה is replaced with ות . For example ''פרה/פרות'' "cow/cows". An example of the dual form is ''יום/ימיים/ימים'' "day/two days/[two or more] days". Some words occur so often in pairs that what is technically the dual form is in practice used for the general plural, such as ''עין/עינים'' "eye/eyes", used even in a sentence like, "The spider has eight eyes." Sometimes, words can change meaning depending on whether the dual or plural form is used, for example; ''יד'' could mean either "hand" or "handle", but ''ידים'' in the dual form always means hands, whilst ''ידות'' in the plural form means handles. Adjectives, verbs, and pronouns have only singular and plural, with the plural forms of these being used with dual nouns.
Modern Hebrew
In
Modern Hebrew, as used in the
State of Israel, there is also a dual number, but its use is very restricted. The dual form is usually used in expressions of time and number. These nouns have plurals as well, which are used for numbers higher than two, for example:
| Singular | Double | Triple |
|---|
| פעם אחת (''once'') | פעמיים (''twice'') | שלוש פעמים (''thrice'') |
| שבוע אחד (''one week'') | שבועיים (''two weeks'') | שלושה שבועות |
| מאה (''one hundred'') | מאתיים (''two hundred'') | שלוש מאות (''three hundred'') |
The dual is also used for some body parts, for instance:
:רגל (''leg'') → רגליים (''legs'')
:אוזן (''ear'') → אוזניים (''ears'')
:עין (''eye'') → עיניים (''eyes'')
:יד (''hand'') → ידיים (''hands'')
In this case, even if there are more than two, the dual is still used, for instance ("a dog has four 'legs'").
The dual in Indo-European languages
Linguists have concluded based on an analysis of living and dead languages that a dual can be reconstructed for the
Proto-Indo-European language, which has been preserved in the earliest records of
Indo-European languages. The best evidence for the dual can be found in
Sanskrit and the
Ancient Greek language used in
Homeric texts, where its use was obligatory for all inflected categories including nouns, verbs, adjectives, and pronouns. The dual can also be found in
Common Slavic and
Proto-Germanic languages, as well as
Old Irish and
Avestan. Based on Sanskrit and the Slavic and Baltic languages, it can be established that the dual in Proto-Indo-European had only three distinct forms: a nominative-accusative-vocative, a dative-ablative-instrumental, and a genitive-locative form.
Although the dual can be reconstructed for Proto-Indo-European, it is currently rarely found in any of the daughter languages. The dual is still actively used in
Scottish Gaelic dialects,
Welsh,
Breton,
Sorbian, and
Slovene. Remnants of the dual can be found in many of the remaining daughter languages, where certain forms of the noun are used with the number two (see below for examples).
The dual in Greek
The dual can be found in Ancient Greek Homeric texts such as the ''
Iliad'' and the ''
Odyssey,'' although its use is only sporadic, owing as much to artistic prerogatives as dictional and metrical requirements within the
hexameter meter. There were only two distinct forms of the dual in Ancient Greek.
In classical Greek, the dual was all but lost, except in the
Attic dialect of
Athens, where it persisted until the fifth century B.C. Even in this case, its use depended on the author and certain stock expressions.
Modern Greek does not have any remnants of the dual.
The dual in the Celtic languages
Reconstructed
Common 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 ''da'' "two". Traces of the dual remain in
Middle Welsh, in nouns denoting pairs of body parts that incorporate the numeral two: e.g. ''deulin'' (from ''glin'' "knee"), ''dwyglust'' (from ''clust'' "ear").
[2]
In the modern languages, there are still significant remnants of dual number in
Scottish Gaelic in nominal phrases containing the numeral ''dà'' (including the higher numerals 12, 22, etc.) As the following table shows, ''dà'' combines with a singular noun, which is
lenited. Masculine nouns take no special inflection, but feminine nouns have a
slenderized dual form, which is in fact identical to the dative singular.
[3]
| Singular | Dual | Plural |
|---|
| ''cu'' ("a dog", ''masculine'') | ''dà chù'' ("two dogs") | ''trì coin'' ("three dogs") |
| ''clach'' ("a stone", ''feminine'') | ''dà chloich'' ("two stones") | ''trì clachan'' ("three stones") |
Languages of the
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 ''daou-/div-'', Welsh ''dau-/deu-/dwy-'', Cornish ''dew-/diw-''). This process is not fully productive, however, and the prefixed forms are semantically restricted. For example, Breton ''daouarn'' (< ''dorn'' "hand") can only refer to one person's pair of hands, not any two hands from two different people. Welsh ''deufis'' must refer to a period of two consecutive months, whereas ''dau fis'' can be any two months.
[4]
The dual in the Germanic languages
The dual was present in all the early Germanic languages, as well as the
proto-language.
Gothic had markings for the first and second person for both the verbs and pronouns, for example ''wit'' "we two" as compared to ''weis'' "we, more than two".
Old English,
Old Norse and other old Germanic languages had dual marking only on first and second person pronouns.
The dual has disappeared as a productive form in all the living languages, with loss of the dual occurring in the North Frisian dialects quite recently
[5]. In
Austro-Bavarian, the old dual pronouns have replaced the standard plural pronouns, for example, accusative ''enk'', ''you plural''. A similar development in the pronoun system can be seen in
Icelandic. Another remnant of the dual can be found in the use of the pronoun ''begge'' ("both") in the Scandinavian languages of
Norwegian,
Danish, and
Swedish. In these languages, in order to state "all + number", the constructions are ''begge to'' ("all two") but ''alle tre'' ("all three"), while the form ''
★ alle to'' is unattested.
The dual in the Baltic Languages
Among the
Baltic languages, the dual form existed but is now nearly obsolete in standard
Lithuanian. It can be occasionally found in poetic contexts and some dialects. The dual form ''Du litu'' was still used on two
litas coins issued in 1925, but the plural form (''2 litai'') is used on modern two litas coins.
| Singular | Dual | Plural |
|---|
| ''vyras'' ("a man") | ''vyru'' ("two men") | ''vyrai'' ("men") |
| ''mergina'' ("a girl") | ''mergini'' ("two girls") | ''merginos'' ("girls") |
| ''einu'' ("I go") | ''einava'' ("We two go") | ''einame'' ("We (more than two) go") |
The dual in the Slavic languages
Common Slavic had a complete singular-dual-plural number system, although the dual paradigms showed considerable
syncretism. Verbs had the same form in the second and third person dual; however, nouns, adjectives, and pronouns inherited the three Proto-Indo-European dual forms.
[6]
Of the living languages, only
Slovene and
Sorbian have preserved the dual number as a productive form. In all of the remaining languages, its influence is still found in the declension of nouns of which there are commonly only two: eyes, ears, shoulders, in certain fixed expressions, and the agreement of nouns when used with numbers.
[7]
In all the languages, the declension of the "two" maintains most of its dual characteristics, which can be verified from the table below.
| language | nom.-acc.-voc. | gen.-loc. | dat. | instr. |
|---|
| 'Common Slavic' | дъва (dǔva) (masc.) / дъвѣ (dǔvě) (fem./nt.) | дъвою (dǔvoju) | дъвѣма (dǔvěma) | дъвѣма (dǔvěma) |
| 'Belarusian' | два (masc./nt.) дзве (fem.) | | | |
| 'Czech' | dva (masc.) / dvě (fem./nt.) | dvou | dvěma | dvěma |
| 'Polish' | dwa (masc./nt) / dwie (fem.)1 | dwu / dwóch | dwu / dwom | dwoma |
| 'Russian' | два (masc./nt. ) / две (fem.) | двух | двум | двумя |
| 'Slovak' | dva / dve | dvoch | dvom | dvoma |
| 'Serbo-Croatian' | два/
dva (masc./nt.) две/двије/
dve/dvije (fem.) | двају/
dvaju (masc./nt.) двеју/двију/
dveju/dviju (fem.)² | двома/
dvоma (masc./nt.) двема/двијема/
dvema/dvijema (fem.) | двома/
dvоma (masc./nt.) двема/двијема/
dvema/dvijema (fem.) |
| 'Slovene' | dva (masc.) dve (fem./nt.) | dveh | dvema | dvema |
| 'Sorbian' | dwaj (masc.) dwě (fem./nt.) | dweju² | dwěmaj | dwěmaj |
| 'Ukrainian' | два / дві | двох | двум | двома |
Notes:
# In Polish, there is a further distinction between animate and inanimate masculine nouns. For animate masculine nouns, the possible nominative forms are ''dwaj, dwóch, or dwu''.
# In Serbo-Croatian and Sorbian, the form given is only for the genitive case; the locative case is then the same as the dative or instrumental cases. The words are first given in Cyrillic, both Ekavian and Ijekavian variant, and then in Latin script, again both Ekavian and Ijekavian variant, if there is a difference between them.
The words ''oba'' and ''obidva'' meaning "both" are declined similarly to the numeral "two."
In Common Slavic, the rules where relatively simple for determining the appropriate case for the noun, when it was used with a numeral. The following rules apply:
# With the numeral "one", both the noun, adjective, and numeral were in the same singular case, with the numeral being declined as an adjective.
# With the numeral "two", both the noun, adjective, and numeral were in the same dual case. There were separate forms for the masculine and neuter-feminine nouns.
# With the numerals "three" and "four," the noun, adjective, and numeral were in the same plural case.
# With any numeral above "four", in the nominative case, the numeral was followed by the noun and adjective in the genitive plural case. For all other cases, both the noun, adjective, and numeral were in the same plural case.
With the loss of the dual in most of the Slavic languages, the above pattern now is only seen in the forms of the numbers for the tens, hundreds, and rarely thousands. This can be seen by examining the following table:
| Language | 10 | 20 | 30 | 50 | 100 | 200 | 300 | 500 |
|---|
| 'Common Slavic' | десѧть (desętǐ) | дъва десѧти (dǔvě desęti) | три десѧте (tri desęte) | пѧть десѧть (pętǐ desętǔ) | съто (sǔto) | дъвѣ сътѣ (dǔvě sǔtě) | три съта (tri sǔta) | пѧть сътъ (pętǐ sǔtǔ) |
| 'Bulgarian' | десет | двадесет | тридесет | петдесет | сто | двеста | триста | петстотин |
| 'Belarusian' | дзесяць | дваццаць | трыццаць | пяцьдзесят | сто | дзвесце | трыста | пяцьсот |
| 'Slovene' | deset | dvajset | trideset | petdeset | sto | dvesto | tristo | petsto |
| 'Polish' | dziesięć | dwadzieścia | trzydzieści | pięćdziesiąt | sto | dwieście | trzysta | pięćset |
| 'Russian' | десять | двадцать | тридцать | пятьдесят | сто | двести | триста | пятьсот |
| 'Serbo-Croatian' | десет/
deset | двадесет/
dvadeset | тридесет/
trideset | педесет/
pedeset | сто/
sto | двеста/двесто/двјеста/двјесто/
dvesta/dvesto/dvjesta/dvjesto1 | триста/тристо/
trista/tristo1 | петсто/
petsto |
| 'Upper Sorbian'[8] | dźesać | dwaceći | třiceći | pjećdźesat | sto | dwě sćě | tři sta | pjeć stow |
| 'Slovak' | desať | dvadsať | tridsať | päťdesiat | sto | dvesto | tristo | päťsto |
| 'Ukrainian' | десять | двадцять | тридцять | п'ятдесят | сто | двісті | триста | п'ятсот |
1-sta is preferred in Serbian, -sto in Croatian for numbers 200 and 300; for numbers of 400 on, only -sto is used
In those languages that lost the dual, the following rules apply (except in Bulgarian and Macedonian, which have lost all declensions):
[9]
# With the numeral "one", both the noun, adjectives, and numeral are in the same singular case, with the numeral being declined as an adjective.
# With the numerals "two", "three" and "four", there are two different possibilities. In Polish, Czech, Slovak, Sorbian, and Ukrainian, the numeral, adjective, and noun are in the same nominative plural case. In Ukrainian, the stress on the noun is that of the genitive singular (or the old dual). In Russian, Belarusian, and Serbo-Croatian, the genitive singular is used for the noun, which in most cases resembles the dual in form is used. The adjective can be either in the genitive singular or plural forms. In all other cases, the appropriate plural form is used.
# With the numerals "five" and above, in the nominative case, the numeral is followed by the noun and adjectives in the genitive plural case. For all other cases, both the noun, adjectives, and numeral are in the same plural case.
#
The resulting changes can be seen in the table below where the word "wolf" is used to form nominative noun phrases with various numerals.
| | "wolf" | "wolves" | "two wolves" | "three wolves" | "five wolves" |
|---|
| noun form | ''nom. sing.'' | ''nom. plur.'' | varies | ''gen. plur.'' |
| 'Common Slavic' | vǐlkǔ | vǐlci | dъva vǐlka (''nom. dual'') | tri vǐlci (''nom. pl.'') | pętǐ vǐlkovǔ |
| 'Czech' | vlk | vlci | dva/tři vlci (''nom. pl.'') | pět vlků |
| 'Polish' | wilk | wilki | dwa/trzy wilki (''nom. pl.'') | pięć wilków |
| 'Ukrainian' | вовк | вовки | два/три вовки (''nom. pl.'') | п'ять вовків |
| 'Russian' | волк | волки | два/три волкa (''gen. sg.'') | пять волков |
| 'Serbo-Croatian' | вук/vuk | вукови/vukovi | два/три вука/dva/tri vuka (''gen. sg.'') | пет вукова/pet vukova |
The dual has also left traces in the declension of nouns describing body parts that humans customarily had two of, for example: eyes, ears, legs, breasts, and hands. Often the plural declension is used to give a figurative meaning. The table below summarizes the key such points.
| Language | Examples |
|---|
| 'Czech' | certain body parts and their modifying adjectives require in the instrumental and genitive plural cases dual forms : ''se svýma očima'' (instrumental dual: "with one's own (two) eyes") or ''u nohou'' (genitive dual: "at the (two) feet"). Colloquial Czech will often substitute the dual instrumental for the literary plural instrumental case. |
| 'Polish' | ''Oko'' ("eye") and ''ucho'' ("ear") have plural stems deriving from old dual forms, and alternative instrumental and genitive plural forms with archaic dual endings: gen. pl. ''oczu/ócz/oczów'', ''uszu''/''uszów''; instr. pl. ''oczami/oczyma'', ''uszami/uszyma''). The declension of ''ręka'' ("hand, arm") also contains old dual forms (nom./acc./voc. pl ''ręce'', instr. pl. ''rękami/'rękoma''', loc. sg./pl. ''rękach/'ręku'''). The historically dual forms are usually used to refer a person's two hands (''dziecko na ręku'' "child-in-arms"), while the regularized plural forms are used elsewhere. Other archaic dual forms, including dual verbs, can be encountered in older literature and in dialects: ''Jak nie 'chceta', to nie 'musita''' "If you don't want to, you don't have to".[10] |
| 'Slovak' | In Slovak, the genitive plural and instrumental plural for the words "eyes" and "ears" has also retained its dual forms: ''očú/očí'' and ''ušú/uší''. |
| 'Ukrainian' | The words eyes and shoulders had dual forms in the instrumental plural case: очима ("eyes") and плечима ("shoulders"). Furthermore, the nominative plural word "вуса", which is the dual of "вус" ("whisker"), refers to the moustache, while the true nominative plural word "вуси" refers to whiskers. |
Slovene
The
Slovene language is the only major Slavic language that retains full grammatical use of the dual, including distinct dual forms for both nouns and verbs. The dual declension merges with the plural in certain nominal cases (e.g., genitive). Note that dual number is compatible with use of the pronoun ''oba(dva)'' or ''obe(dve)'' ("both").
Nominative case of noun "wolf", with and without numerals:
| | nom. sg. (wolf) | nom. pl. (wolves) | 2 wolves (nom. dual) | 3 (or 4) wolves (nom. pl.) | 5 (+) wolves (gen. pl.) |
|---|
| 'Slovene' | volk | volkovi | dva volkova | trije volkovi | pet volkov |
The dual is recognised by many Slovene speakers as one of the most distinctive features of the language and a mark of recognition, and is often mentioned in tourist brochures.
For verbs, the endings in the present tense are given as ''-va'', ''-ta'', ''-ta''. The table below shows a comparison of the conjugation of the verb 'oddati', which means 'to give away' and belongs to Class I in the singular, dual, and plural.
| | 'Singular' | 'Dual' | 'Plural' |
|---|
| First Person | odd'am' | odd'ava' | odd'amo' |
| Second Person | odd'aš' | odd'ata' | odd'ate' |
| Third Person | odd'a' | odd'ata' | odd'ajo' |
In the imperative the endings are given as '-iva' for the first person dual and '-ita' for the second person dual. The table below shows the imperative forms for the verb 'hoditi' (to walk) in the first and second persons of the imperative.
| | 'Singular' | 'Dual' | 'Plural' |
|---|
| First Person | | hodiva | hodimo |
| Second Person | hodi | hodita | hodite |
Languages with dual number
★
Proto-Indo-European language
★
★
Avestan
★
★
Scottish Gaelic (only nouns, only following the numeral for 'two')
★
★
Ancient Greek
★
★
Old Irish
★
★
Old Russian
★
★
Sanskrit
★
★
Slovene
★
★
Lower Sorbian
★
★
Upper Sorbian
★
Proto-Uralic language
★
★
Khanty
★
★
Mansi
★
★
Nenets
★
★
Sami languages
★
Afro-asiatic languages
★
★
Akkadian (Assyrian and Babylonian)
★
★
Arabic :
Classical and
Modern Standard Arabic
★
★
Biblical Hebrew
★
★
Egyptian (ancient up to and including
Coptic)
★
★
Maltese
★
Inuktitut
★
Quenya (not a natural language)
★
American Sign Language
★
Māori (only the personal pronouns)
★
Samoan (only the personal pronouns)
Notes
1. Dual Personal Pronouns and Dual Verbs in Hebrew Gary Rendsburg The Jewish Quarterly Review, New Ser., Vol. 73, No. 1 (Jul., 1982), pp. 38-58
doi:10.2307/1454459.
2. A Concise Comparative Celtic Grammar, , Henry, Lewis, Vandenhoeck & Ruprecht, 1989, ISBN 3-525-26102-0 A Grammar of Old Irish, , Rudolf, Thurneysen, Dublin Institute for Advanced Studies, 1993, ISBN 1-85500-161-6 A Grammar of Middle Welsh, , D. Simon, Evans, Dublin Institute for Advanced Studies, 1989, ISBN 1-85500-000-8
3. Scottish Gaelic in Three Months, , Roibeard, Ó Maolalaigh, Hugo's Language Books, , ISBN 978-0-85285-234-7
4. Is there a Category of Dual in Breton or Welsh?, , Johannes, Heinecke, Journal of Celtic Linguistics, 2002
5. Howe, Stephen. ''The Personal Pronouns in the Germanic Languages. A study of personal pronoun morphology and change in the Germanic languages from the first records to the present day''. [Studia Linguistica Germanica, 43]. Berlin: de Gruyter, 1996. (xxii + 390 pp.) pp. 193-195.
6. Common Slavic Grammar from the Indo-European Database
7. Mayer, Gerald L. (1973) "Common Tendencies in the Syntactic Development of 'Two', 'Three,' and 'Four' in Slavic." ''The Slavic and East European Journal'' 17.3:308–314.
8. These forms are taken from De Bray, R. G. A. ''Guide to the Slavonic Languages''. London, 1951.
9. R. G. A. De Bray, ''op. cit.''
10. A Grammar of Contemporary Polish, , Oscar E., Swan, Slavica, , ISBN 0-89357-296-9
See also
★
Grammatical number
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