Interlingue grammar

Grammatical endings are used, though to a far lesser extent than more schematic planned languages such as Esperanto and Ido in which parts of speech are marked with obligatory endings.[2] Only a few parts of speech (such as verbs in the infinitive) in Interlingue have entirely obligatory endings, while many others either have endings the usage of which is optional and sometimes recommended.[3] Some grammatical endings are:

• ar, er, ir: verb infinitive. far (to do), posser (be able), scrir (to write)
• e: the general substantival (noun) ending used obligatorily to differentiate nouns from other parts or speech, for reasons of pronunciation, or optionally for euphony. Examples of obligatory -e endings: capitale (capital, noun) vs. capital (capital, adjective), contenete (content) vs, contenet (contained), sud (south, adjective) vs. sude (south as an independent noun, as in the north and the south). A final -e is recommended in words ending with -s to avoid confusion with the plural (curse, sense), -ir, -er- and -ar endings to avoid confusion with the verb infinitive (dangere, desire, papere), and other such areas where its addition aids in differentiation or pronunciation.[3] Optional -e endings: can or cane (dog), Pentecost or Pentecoste (Pentecost). The -e and other endings are often omitted for poetic or euphonic reasons.[4]
• i: the general adjectival ending, similar to -e in usage. Examples of obligatory -i endings: pigri (lazy) and acri (sharp) to enable pronunciation, verdi (green, adjective) to distinguish from verde (green, noun). Examples of optional -i endings: etern vs. eterni (eternal), imens vs. imensi (immense).
• a: nouns that end in e formed from an -ar verb are often written with the -a ending if one wishes to emphasize the verbal (active) aspect. A me veni un pensa (a thought occurs to me) vs. Penses e paroles (thoughts and words). The a ending also makes nouns feminine: anglese (English person), angleso (Englishman), anglesa (English woman). This does not apply to nouns that on their own indicate the gender (patre, matre).[5]
• o: indicates the masculine gender in the same way a indicates the feminine.[1]

Interlingue has two forms for the personal pronouns: one for the subject form (nominative), and one for the object form (accusative or dative, i.e. the oblique form):[1]

The formal second person is vu,[1] which is also the second person plural. The indefinite personal pronoun "one" is on.[6] If necessary, one can specify the gender of third person plural by using illos (masculine) or ellas (feminine).[1]

In the object form the pronouns are: me, te, le, la, it, nos, vos, and les (with los and las as specific masculine and feminine forms, respectively). In the oblique case, the pronouns are me, te, il (or le), noi (or nos), voi (or vos), and ili (or les), varying by user and situation for pronouns except me and te.[8] The possessive pronouns are mi, tui, su (his/her/its), nor, vor and lor.[1] They may be pluralized: li mi (mine, singular), li mis (mine, plural), li nor (ours, singular), li nores (ours, plural).[9]

Interlingue has primary adverbs and derived adverbs. Primary adverbs are not generated from other parts of speech and are thus not formed using any special endings: tre (very), sempre (always), etc.[1]

Derived adverbs are formed by adding the suffix -men to an adjective (rapid = quick, rapidmen = quickly), cognate with French -ment, Italian -mente, and others. The ending -men was inspired by Provençal and spoken French (which does not pronounce the t in -ment) and chosen over -mente to avoid clashing with the noun ending -ment and other nouns in the language derived from the past tense in -t.[17][18] Adjectives may be used as adverbs when the sense is clear:[1][19]

Il ha bon laborat = He has worked well ("He has worked good")

Noi serchat long = We looked for a long time ("We searched long")

Dr. F. Haas in 1956 grouped the most common adverbs by type as below.

While correlatives were not made to match a pre-determined scheme (such as the correlatives in Esperanto[20]), the majority match the prefixes and suffixes in the chart below.

Notes on the correlatives:[21]

Alcun (some) and necun (no, none) are respectively the adjectives of alquel and nequel.

The -qui series has optional accusative forms ending in -em: quem, alquem, nequem.

The -al series is adverbialized with the -men ending: qualmen (how) talmen (that way).

Correlatives can take the plural ending: queles, quales, tis, omnis, etc.

Ci (here) and ta (there) can be affixed to ti and to to indicate proximity or distance: ti libre (this book), ti-ci libre (this book here), ti-ta libre (that book there), tis (these), tis-ci (these here), tis-ta (those there), to-ci (this here), to-ta (that there).

Many derivatives are formed from the correlatives: qualitá from qual + itá, quantitá from quant + -itá, omnipotent from omni + potent.

Though seemingly favourable to the Romance language family, de Wahl did not see Occidental as a Romance language and did not tolerate any nationalism or chauvinism in the choice of words for the language. His opinion on justice in the choice of vocabulary was that: "However many special, new, significant words each [culture] has respectively added to the common human culture, that much they receive."[22] Below are examples he provided of source languages and what they are particularly known for around the world (why they are included in Occidental).[22]

An example of derivation from the magazine Cosmoglotta.

Flowchart demonstrating derivation of nouns from verbs using de Wahl's rule.

The application of de Wahl's rule to verbs, and the usage of numerous suffixes and prefixes, was created to resolve irregularities that had plagued creators of language projects before Occidental, who were forced to make the choice between regularity and unnatural forms, or irregularity and natural forms. The prevailing view before its application was that natural forms needed to be sacrificed for the sake of regularity, while those that opted for naturalism were forced to admit numerous irregularities when doing so (Idiom Neutral for example had a list of 81 verbs with special radicals[23] used when forming derivatives), a paradox summed up by Louis Couturat in 1903 as follows:[24]

In short, one finds oneself confronted by the antinomy that the words that are international are not regular, and the words that are regular are not international; the prevailing opinion [of naturalists such as Julius Lott and de Wahl] was that regularity should be sacrificed for internationality in the formation of words.

The rules created by de Wahl to resolve this were first described in 1909[25] in the Discussiones of Peano's Academia pro Interlingua and are as follows:

1. If, after the removal of -r or -er of the infinitive, the root ends in a vowel, the final -t is added. Crear (to create), crea/t-, crea/t/or, crea/t/ion, crea/t/iv, crea/t/ura.
2. If the root ends in consonants d or r, they are changed into s: decid/er (to decide), deci/s-, deci/s/ion deci/s/iv. Adherer (to adhere), adhe/s-, adhe/s/ion
3. In all other cases, with six exceptions, the removal of the ending gives the exact root: duct/er, duct-, duct/ion.

Once these rules were applied, Occidental was left with six exceptions. They are:[26]

1. ced/er, cess- (concession)
2. sed/er, sess- (session)
3. mov/er, mot- (motion)
4. ten/er, tent- (temptation)
5. vert/er, vers- (version)
6. veni/r, vent- (advent)

Suffixes are added either to the verbal root or the present theme of the verb (the infinitive minus -r). An example of the latter is the suffix -ment: move/r, move/ment (not movetment), experi/r, experi/ment (not experitment), and -ntie (English -nce): tolera/r (tolerate), tolera/ntie, existe/r (exist), existe/ntie.[27]

The major prefixes and suffixes used in word derivation in Interlingue are added to either the present theme (infinitive minus -r), verbal root (infinitive minus two preceding vowels), or perfect theme (present theme + t or +s for verbs finishing with -d or -r) of verbs, as well as other types of speech. The below is a sample of some of the affixes used.[5]