As in English, nouns cannot be identified by a constant and specific feature of their forms. The great majority of nouns end in one of the vowels a, o, e, or the consonants l, n, r. But these terminations occur with other words too. There are, again as in English, a number of suffixes which occur only with nouns. Otherwise nouns are recognized by the function they perform in a sentence.
There is no GRAMMATICAL GENDER. The terminations of nouns have no grammatical value and may be considered accidental.
tabula 'table'
pagina 'page'
homine 'man, human being'
tempore 'time'
uso 'use'
fructo 'fruit'
uxor 'wife'
fun 'rope'
galon 'braid, galloon'
libertate 'liberty'
generation 'generation'
gas 'gas'
roc 'rook, castle'
When the termination o occurs - as it frequently does - in a word designating a MALE being, the corresponding FEMALE can be represented by the same word with the substituted ending a. The rule works also in reverse order.
asino 'donkey'; hence: asina 'female donkey'
missionario 'missionary'; hence: missionaria 'woman missionary'
americano 'American'; hence: americana 'American (girl or woman)'
oca 'goose'; hence: oco 'gander'
ciconia 'stork'; hence: ciconio '(male) stork'
Note: The inference that a word like musca 'fly' would permit the use of the male form musco is as justified and also as incongruous as the suggestion that English can form the word 'he-fly.' On the formation of female nouns by means of the suffixes -essa and -trice, see §138, §152
The PLURAL is formed by the addition of s or - after a consonant - of es. Final c changes before es to ch.
tabulas, paginas, homines, tempores, usos, fructos, uxores, aeres, funes, galones, libertates, generationes, gases, roches
Irregular plurals occur only in "guest words" which have retained their foreign identity.
le test: le tests [English]
le lied: le lieder [German]
le addendum: le addenda [Neo-Latin]
le: Abruzzi [Italian]
Learned terms ending in -is form their plural as though the singular had a final -e: genesis (or genese) > geneses; hepatitis > hepatites.
Singular compounds with second elements in the plural have no distinct plural.
un guardacostas: duo guardacostas (coastguard)
un rumpenuces: duo rumpenuces (nutcracker)
un paracolpos: duo paracolpos (bumper)
There are no CASE FORMS. The functions of the genitive and dative in other languages are taken over by prepositions.
de Deo 'God's, of God'
a Deo 'God, to God'
Ille invia flores a su matre 'He sends his mother flowers, He sends flowers to his mother'
Ilia recipe le flores de su filio 'She receives her son's flowers'
Nos paga taxas al governamento 'We pay the government tax money, We pay tax money to the government'
le debitas del governamento 'the government's debts, the debts of the government'
On the formation of nouns as well as of derivatives from them, see §138, §139, §140, §141, §152, §154.
The way nouns are used in the sentence does not differ materially from English norms. Note, however, that the almost unlimited use of NOUNS WITH ADJECTIVAL FUNCTIONS is an English trait not shared by Interlingua.
'winter weather' (= wintry weather, weather of winter) tempore hibernal, tempore de hiberno
'research laboratory' (= laboratory of research) laboratorio de recerca
'fall coat' (= coat of fall, coat for fall) mantello de autumno, mantello pro autumno
'night watchman' (= watchman of night) guarda de nocte
'milk bottle' (= bottle of milk, bottle for milk) bottilia de lacte, bottilia a lacte
'night song' (= song of night, nocturnal song) canto de nocte, canto nocturne
PROPER NOUNS functioning in English as adjectives - as e.g. in 'Diesel engine,' 'Geiger counter,' etc. - remain unmodified proper nouns in the Interlingua and are preceded by the noun they qualify in English. The pattern used is that followed in English in the case of titles: Doctor Diesel, Professor Diesel, engine Diesel; etc. The proper names take no plural -s.
'Geiger counter(s)' contator Geiger, contatores Geiger
'Diesel engine(s)' motor Diesel, motores Diesel
'Roentgen rays' radios Röntgen
'Heaviside layer' strato Heaviside
There is a very free use of APPOSITION with one member often corresponding to an English noun with adjectival functions.
foresta virgine 'virgin forest'
arbore nano 'dwarf tree'
wagon restaurante 'dining car'
nave domo 'house boat'
homine machina 'human machine'
The use of apposition is very frequent with nouns of agents and the like which thus become indistinguishable from adjectives.
mi amico mazdaista 'my Mazdaist friend'
apparato generator 'generating device'
uxor puera 'child wife'
In the plural the appositive may take an -s. Without it the appositive is more clearly adjectival. One would say: uxores pueras but apparatos generator, forestas virgine, etc.
When the appositive has distinct forms for male and female, their use is governed by the fact of sex.
mi amico cantator e mi amica cantatrice
'my singer friend (masc.) and my singer friend (fem.)'