Esperanto grammar

Esperanto is the most widely used constructed language intended for international communication; it was designed with highly regular grammatical rules, and is therefore considered easy to learn.

In addition to indicating direct objects, the accusative/allative case is used with nouns, adjectives and adverbs for showing the destination of a motion, or to replace certain prepositions; the nominative/oblique is used in all other situations.

The case system allows for a flexible word order that reflects information flow and other pragmatic concerns, as in Russian, Greek, and Latin.

The words iu and unu (or their plurals iuj and unuj) may be used somewhat like indefinite articles, but they're closer in meaning to "some" and "a certain" than to English "a".

[1] For example, it is used to introduce new participants (Unu viro ekvenis al mi kaj diris ... 'A man came up to me and said ...').

Often with a nominal or verbal root, the English equivalent is a prepositional phrase: parole (by speech, orally); vide (by sight, visually); reĝe (like a king, royally).

This requirement allows for the word orders adjective–noun and noun–adjective, even when two noun phrases are adjacent in subject–object–verb or verb–subject–object clauses: Agreement clarifies the syntax in other ways as well.

^1 Zamenhof introduced a singular second-person pronoun ci, to be used in translations from languages where the T–V distinction was important, but he discouraged its use.

[5] He added it in the Dua Libro in 1888 clarifying that "this word is only found in the dictionary; in the language itself it is hardly ever used",[6] and excluded it from the list of pronouns in the Fundamento.

Esperanto does not have separate forms for the possessive pronouns; this sense is generally (though not always) indicated with the definite article: la mia (mine).

Thus the verbal root far- (do, make) has been unofficially used without a part-of-speech suffix as a preposition "by", marking the agent of a passive participle or an action noun in place of the standard de.

Impersonal subjects are not used: pluvas (it is raining), estas muso en la domo (there is a mouse in the house).

As in English, the Esperanto present tense may be used for generic statements such as "birds fly" (la birdoj flugas).

In addition to carrying aspect, participles are the principal means of representing voice, with either nt or t following the vowel (see next section).

The tense and mood of esti can be changed in these compound tenses: Although such periphrastic constructions are familiar to speakers of most European languages, the option of contracting [esti + adjective] into a verb is theoretically possible for adjectival participles: In practice, only a few of these forms, notably -intus (conditional past progressive) and -atas (present passive), have entered the common usage.

Just after the recount of the 2000 United States presidential election: Tense-neutral words such as prezidento and studento are formally considered distinct nominal roots, not derivatives of the verbs prezidi and studi.

Basic Esperanto conjunctions are kaj (both/and), aŭ (either/or), nek (neither/nor), se (if), ĉu (whether/or), sed (but), anstataŭ (instead of), kiel (like, as), ke (that).

These, along with compounding, decrease the memory load of the language, as they allow for the expansion of a relatively small number of basic roots into a large vocabulary.

For example, the Esperanto root vid- (see) regularly corresponds to several dozen English words: see (saw, seen), sight, blind, vision, visual, visible, nonvisual, invisible, unsightly, glance, view, vista, panorama, observant etc., though there are also separate Esperanto roots for a couple of these concepts.

An unambiguous system based on adding the Esperanto suffix -iliono to numerals is generally used instead, sometimes supplemented by a second suffix -iliardo:[29] Note that these forms are grammatically nouns, not numerals, and therefore cannot modify a noun directly: mil homojn (a thousand people [accusative]) but milionon da homoj (a million people [accusative]).

The particle po is used to mark distributive numbers, that is, the idea of distributing a certain number of items to each member of a group: Note that particle po forms a phrase with the numeral tri and is not a preposition for the noun phrase tri pomojn, so it does not prevent a grammatical object from taking the accusative case.

Because of adjectival agreement, an adjective may be separated from the rest of the noun phrase without confusion, though this is only found in poetry, and then only occasionally:[33] Possessive pronouns strongly favor initial position, though the opposite is well known from Patro nia 'Our Father' in the Paternoster.

Less flexibility occurs with demonstratives and the article, with demonstrative–noun being the norm, as in English: Noun–demonstrative order is used primarily for emphasis (plumo tiu 'that pen').

Again, this is one of the situations where adjectives come after nouns in English: Changing the word order here can change the meaning, at least with the correlative nenio 'nothing': With multiple words in a phrase, the order is typically demonstrative/pronoun–numeral–(adjective/noun): In prepositional phrases, the preposition is required to come at the front of the noun phrase (that is, even before the article la), though it is commonly replaced by turning the noun into an adverb: Constituent order within a clause is generally free, apart from copular clauses.

Copulas are words such as esti 'be', iĝi 'become', resti 'remain', and ŝajni 'seem', for which neither noun phrase takes the accusative case.

When two noun phrases are linked by a copula, greater chance exists for ambiguity, at least in writing where prosody is not a cue.

They follow the conjunction ke 'that', as in, Esperanto's vocabulary, syntax, and semantics derive predominantly from Standard Average European languages.

Frequently mentioned is Esperanto's agglutinative morphology based on invariant morphemes, and the subsequent lack of ablaut (internal inflection of its roots), which Zamenhof thought would prove alien to non-European language speakers.

Historically, many European languages have expanded the range of their 'weak' inflections, and Esperanto has merely taken this development closer to its logical conclusion, with the only remaining ablaut being frozen in a few sets of semantically related roots such as pli, plej, plu (more, most, further), tre, tro (very, too much), and in the verbal morphemes ‑as, ‑anta, ‑ata; ‑is, ‑inta, ‑ita; ‑os, ‑onta, ‑ota; and ‑us.

The Pater noster, from the first Esperanto publication in 1887, illustrates many of the grammatical points presented above: Patro nia, kiu estas en la ĉieloj, sanktigata estu Via nomo.