Editing Esperanto grammar (section)

==Verbs==
All verbal inflection is regular. There are three tenses of the [[indicative mood]]. The other moods are the [[conditional mood|conditional]] and [[Volitive mood|volitive]] (treated as the [[Jussive mood|jussive]] by some). There is also the [[infinitive]]. No [[Grammatical aspect|aspectual]] distinctions are required by the grammar, but derivational expressions of [[Lexical aspect|Aktionsart]] are common.

Verbs do not change form according to their [[subject (grammar)|subject]]. ''I am, we are,'' and ''he is'' are simply ''mi estas, ni estas,'' and ''li estas,'' respectively. Impersonal subjects are not used: ''pluvas'' (it is raining), ''estas muso en la domo'' (there is a mouse in the house).

Most verbs are inherently [[Transitive verb|transitive]] or [[Intransitive verb|intransitive]]. As with the inherent part of speech of a root, this is not apparent from the shape of the verb and must simply be memorized. Transitivity is changed with the affixes ''-ig-'' (the transitivizer/[[causative]]) and ''-iĝ-'' (the intransitivizer/[[middle voice]]) after the root; for example:
:''akvo bolas je cent gradoj'' (water boils at 100 degrees)
:''ni bol'''ig'''as la akvo'''n''''' (we boil the water)
(''Boli'' is an intransitive verb; the ''-ig-'' affix makes it transitive.)
:''mi movis la biciklo'''n''' al la ĝardeno'' (I moved the bicycle to the garden)
:''la biciklo mov'''iĝ'''is tre rapide'' (the bicycle moved very fast)
(''Movi'' is a transitive verb; the ''-iĝ-'' affix makes it intransitive.)

===The verbal paradigm===
The tenses have characteristic vowels. Namely, ''a'' indicates the present tense, ''i'' the past, and ''o'' the future. (However, ''i'' on its own is used for the infinitive.)

{| class=wikitable
!
![[indicative mood|Indicative]]
![[Participle|Active participle]]
![[Participle|Passive participle]]
![[conditional mood|Conditional]]
![[Volitive mood|Volitive]]
![[Infinitive]]
|-
![[past tense|Past]]
|align="center"| -is
|align="center"| -inta
|align="center"| -ita
| rowspan="3" | -us
|align="center" rowspan="3"|-u
|align="center" rowspan="3"| -i
|-
![[present tense|Present]]
|align="center"| -as
|align="center"| -anta
|align="center"| -ata
|-
![[future tense|Future]]
|align="center"| -os
|align="center"| -onta
|align="center"| -ota
|}

The verbal forms may be illustrated with the root ''esper-'' (hope):
:''esperis'' (hoped, was hoping)
:''esperas'' (hopes, is hoping)
:''esperos'' (shall hope, will hope)
:''esperus'' (were to hope, would hope)
:''esperu'' (hope, hope! [a command])
:''esperi'' (to hope)

A verb can be made emphatic with the particle ''ja'' (indeed): ''mi ja esperas'' (I do hope), ''mi ja esperis'' (I did hope).

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

The Esperanto [[future tense|future]] is a true tense, used whenever future time is meant. For example, in English "(I'll give it to you) when I see you" the verb "see" is in the present tense despite the time being in the future; in Esperanto, future tense is required: ''(Mi donos ĝin al vi) kiam mi vidos vin''.

In [[indirect speech]], Esperanto tense is [[relative tense|relative]].<ref>[https://bertilow.com/pmeg/gramatiko/subfrazoj/nerekta_parolo/verboformoj.html ''Plena Manlibro de Esperanta Gramatiko'']</ref> This differs from English absolute tense, where the tense is past, present, or future of the moment of speaking: In Esperanto, the tense of a [[subordinate clause|subordinate verb]] is instead anterior or posterior to the time of the main verb. For example, "John said that he would go" is in Esperanto ''Johano diris, ke li iros'' (lit., "John said that he will go"); this does not mean that he will go at some point in the future from now (as "John said that he will go" means in English), but that at the time he said this, his going was still in the future.

===Mood===
The [[conditional mood]] is used for such expressions as ''se mi povus, mi irus'' (if I could, I would go) and ''se mi estus vi, mi irus'' (if I were you, I'd go).

The [[volitive mood]] is used to indicate that an action or state is desired, requested, ordered, or aimed for.<ref>{{cite web|url=https://bertilow.com/pmeg/gramatiko/verboj/vola.html|title=Vola modo – U-finaĵo|last=Wennergren|first=Bertilo|author-link=Bertilo Wennergren|website=Plena Manlibro de Esperanta Gramatiko|access-date=2021-05-27|quote=U-formo montras, ke la ago aŭ stato ne estas reala, sed dezirata, volata, ordonata aŭ celata.|trans-quote=a U form shows that the action or state is not real, but desired, wanted, ordered, or aimed for.}}</ref> Although the verb form is formally called volitive,<ref>{{cite book|last1=Kalocsay|first1=Kálmán|author-link1=Kálmán Kalocsay|last2=Waringhien|first2=Gaston|author-link2=Gaston Waringhien|date=1985|title=Plena Analiza Gramatiko|url=http://luisguillermo.com/PAG/Plena_Analiza_Gramatiko_(K._Kalocsay,_G._Waringhien).pdf#page=127|location=Rotterdam|publisher=[[Universal Esperanto Association]]|page=133|isbn=9789290170327}}</ref><ref>{{cite web|url=https://lernu.net/eo/gramatiko/verboj#volitivo|title=Finitivaj verboj: Volitivo (imperativo)|last=Wennergren|first=Bertilo|author-link=Bertilo Wennergren|website=[[lernu!]]|access-date=2021-05-27}}</ref> in practice it can be seen as a broader [[deontic mood|deontic]] form rather than a pure volitive form, as it is also used to express orders and commands besides wishes and desires. It serves as the [[Imperative mood|imperative]] and performs some of the functions of a [[subjunctive]]:
:''Iru!'' (Go!)
:''Mi petis, ke li venu.'' (I asked him to come.)
:''Li parolu.'' (Let him speak.)
:''Ni iru.'' (Let's go.)
:''Benu ĉi tiun domaĉon.'' (Bless this shack.)
:''Mia filino belu!'' (May my daughter be beautiful!)

===Aspect===
Verbal [[Grammatical aspect|aspect]] is not grammatically required in Esperanto. However, aspectual distinctions may be expressed via participles (see below), and the Slavic aspectual system survives in two [[Lexical aspect|aktionsart]] affixes, [[perfective aspect|perfective]] (often inceptive) ''ek-'' and [[imperfective aspect|imperfective]] ''-ad.'' Compare,
:''Tio ĉi interesis min'' (This interested me)
and,
:''Tio ĉi '''ek'''interesis min'' (This '''caught''' my interest).
Various prepositions may also be used as aktionsart prefixes, such as ''el'' (out of), used to indicate that an action is performed to completion or at least to a considerable degree, also as in Slavic languages, as in,
:''Germanan kaj francan lingvojn mi '''el'''lernis en infaneco'' (I learned French and German in childhood).

===Copula===
The verb ''esti'' (to be) is both the [[copula (linguistics)|copula]] ("X is Y") and the existential ("there is") verb. As a copula linking two [[noun phrase]]s, it causes neither to take the accusative case. Therefore, unlike the situation with other verbs, word order with ''esti'' can be semantically important: compare ''hundoj estas personoj'' (dogs are people) and ''personoj estas hundoj'' (people are dogs).

Existential verbs do not use [[dummy pronoun]]s. Thus, the phrase ''estas pomo'' (there is an apple) does not contain a leading pronoun, as does its English translation.

One sometimes sees ''esti''-plus-adjective rendered as a verb: ''la ĉielo estas blua'' as ''la ĉielo bluas'' (the sky is blue). This is a stylistic rather than grammatical change in the language, as the more economical verbal forms were always found in poetry.<ref>However, the reverse – changing verbs to adjectives – does not behave in the same way: ''Morti'' (to die) does not have the same meaning as ''esti morta'' (to be dead).</ref>