Interlingue grammar

**Interlingue** is a constructed language. It was called *Occidental* between 1922 and 1947. Edgar de Wahl, one of the first Esperantists, created it. De Wahl was from the city of Tallinn in Estonia, which was in the Russian Empire but later became its own country. He spoke German, Russian, Estonian and French since he was a child and had natural ability in languages. He is often called *de Wahl*.

Interlingue looks a lot like languages in the Romance language family: French, Spanish, Italian, and so on. De Wahl made a rule called De Wahl's rule that made changing verbs to nouns easier and more regular. For example, the word **exploder** (to explode) regularly changes its **d** to **s** (making explo**s**ion) when following this rule.

## Alphabet and pronunciation 
Interlingue is written with 26 Latin letters: a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, z. The letters of the alphabet are pronounced as *a, be, ce, de, e, ef, ge, ha, i, jot, ka, el, em, en, o, pe, qu, er, es, te, u, ve, duplic ve, ix, ypsilon*, and *zet*. Accents are written on the five vowels to indicate irregular stress, with the acute accent (á é í ó ú) preferred, but others (è, ê, etc.) permitted.
* **c** when before e and i = [ts]: *cive*, *helice*
* **g** when before e and i = English s in pleasure: *plage, giraffe*; but elsewhere c and g are as in can, go
* **ss** = [s] as in *pass*
* **s** between vowels = [z]: *rose, positiv*
* **z** = [dz]
* **zz** = [ts]
* **ch** = [ʃ], English sh: *chambre*
* **j** = [ʒ], English s in pleasure
* **t** as [t], except when followed by ia, io, iu, or ie and not preceded by an s. Thus the t in *nation* is pronounced [ts] but in *bastion* as [t].

Other doubled consonants are pronounced as a single consonant, unless when separated they would be pronounced differently. Ex. **grammatica** is pronounced as if written **gramatica**, but **occidental** and **suggestion** are pronounced as if written as **oc** followed by **cidental**, and **sug** followed by **gestion**.

## Article 
Like English, Interlingue has a definite article and an indefinite article. The definite article (the) is *li*, and the indefinite (a, an) is *un*. Plural of a noun is made by adding *-s* after a vowel, or *-es* after most consonants. Of these, the forms **lu** and **lis** are most common: **lu** in the same sense as Spanish *lo* and English *that which*, as in **Ne li aprension de un lingue es lu essential, ma su usation** (*that which* is essential is not the learning of a language, but using it), and **lis** to change to plural words that are difficult to make plural on their own: **lis s** (the s's).

## Personal pronouns
Interlingue has two forms for the personal pronouns: one for the subject form (nominative), and one for the object form (accusative or dative).

Grammatical endings are used, but less than in Esperanto and Ido in which parts of speech are marked with obligatory endings. Only a few parts of speech (such as verb infinitives) in Interlingue have entirely obligatory endings, while many others either have endings the usage of which is optional and sometimes recommended. Optional -e endings: can or can**e** (dog), Pentecost or Pentecost**e** (Pentecost).
* **i**: the general adjectival ending, similar to -e in usage. Examples of obligatory -i endings: pigr**i** (lazy) and acr**i** (sharp) to enable pronunciation, verd**i** (green, adjective) to distinguish from verd**e** (green, noun). Examples of optional -i endings: etern vs. etern**i** (eternal), imens vs. imens**i** (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 pens**a** (a thought occurs to me) vs. Pens**e**s e paroles (thoughts and words). The **a** ending also makes nouns feminine: angles**e** (English person), angles**o** (Englishman), angles**a** (English woman). This does not apply to nouns that on their own indicate the gender (patre, matre).
* **o**: indicates the masculine gender in the same way **a** indicates the feminine.

## Correlatives 
Notes on the correlatives:

**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.**

## Verbs 
Verbs in Interlingue have three endings: -**ar**, -**er**, and -**ir**. Conjugation is performed with a combination of endings and auxiliary verbs. The verb **esser** (to be) is exceptional in being written **es** in the present  tense, though the **esse** form is seen in the imperative.

## Adverbs 
Interlingue has **primary adverbs** and **derived adverbs**. Primary adverbs are adverbs without special endings: *tre* (very), *sempre* (always), etc. The ending may be omitted when the meaning is clear: **tu deve far it rapid(men)** = you must do it quick(ly).

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

## References