# Esperanto grammar: overview, endings and rules

Source: https://esperantopedia.org/grammar/
Language: en
Updated: 2026-10-28

> Esperanto grammar fits on one card: 11 endings mark nouns, adjectives, tenses, plural and object, and there are no irregular verbs. See the table.

Esperanto grammar rests on one idea: roots never change, and a small set of endings always means the same thing. A word ending in *-o* is a noun, *-a* an adjective, *-as* a verb in the present. There are no irregular verbs, no irregular plurals and no grammatical gender.

The [16 rules](https://esperantopedia.org/grammar/16-rules/) that L. L. Zamenhof published in 1887 sketch this system; the core below covers most sentences you will meet.

## The whole grammar on one card

The official dictionary of the Akademio de Esperanto counts exactly 11 grammatical endings:

| Ending | What it marks | Example | Meaning |
|---|---|---|---|
| -o | noun | *domo* | "house" |
| -a | adjective | *granda* | "big" |
| -e | adverb | *rapide* | "quickly" |
| -i | infinitive | *lerni* | "to learn" |
| -as | present tense | *mi lernas* | "I learn, I am learning" |
| -is | past tense | *mi lernis* | "I learned" |
| -os | future tense | *mi lernos* | "I will learn" |
| -us | conditional | *mi lernus* | "I would learn" |
| -u | command, wish | *lernu!* | "learn!" |
| -j | plural | *domoj* | "houses" |
| -n | object, direction | *domon* | "house" (as object) |

Endings stack in a fixed order: word class, then *-j*, then *-n*: *grandajn domojn* – "big houses" (as object). Adjectives copy the *-j* and *-n* of their noun, as shown on [nouns and adjectives](https://esperantopedia.org/grammar/nouns-adjectives/).

[Verbs](https://esperantopedia.org/grammar/verbs/) never take *-j* or *-n*, and they do not change for person: *mi lernas, vi lernas, ili lernas* – "I learn, you learn, they learn".

## The endings in sentences

Each ending at work in a short everyday sentence:

- **-o**: *La domo estas nova.* – "The house is new."
- **-a**: *Ni loĝas en nova domo.* – "We live in a new house."
- **-e**: *Ŝi parolas malrapide kaj klare.* – "She speaks slowly and clearly."
- **-i**: *Mi volas lerni Esperanton.* – "I want to learn Esperanto."
- **-as**: *Nun mi lernas la vortojn.* – "Now I'm learning the words."
- **-is**: *Hieraŭ ni lernis dum unu horo.* – "Yesterday we studied for an hour."
- **-os**: *Morgaŭ mi skribos al vi.* – "Tomorrow I'll write to you."
- **-us**: *Se mi havus tempon, mi vojaĝus.* – "If I had time, I would travel."
- **-u**: *Venu kun ni!* – "Come with us!"
- **-j**: *Miaj amikoj estas en la parko.* – "My friends are in the park."
- **-n**: *Mi vidas grandan ŝipon.* – "I see a big ship."
- **All together**: *Miaj novaj amikoj rapide lernis la gravajn vortojn.* – "My new friends quickly learned the important words."

## The other building blocks

- **One article.** *La* means "the" for every gender and number, and there is no word for "a". See [the article](https://esperantopedia.org/grammar/article/).
- **Free word order.** Because *-n* marks the object, *La hundo vidas la katon* and *La katon vidas la hundo* both mean "The dog sees the cat". See [the accusative](https://esperantopedia.org/grammar/accusative/).
- **Word building.** Prefixes and suffixes turn one root into many words: *sana* – "healthy", *malsana* – "ill", *malsanulo* – "patient", *malsanulejo* – "hospital". See [word building](https://esperantopedia.org/grammar/word-building/).
- **45 correlatives.** A 5 × 9 grid of question and answer words: *kiu* – "who", *tiu* – "that one", *ĉiu* – "everyone". See [correlatives](https://esperantopedia.org/grammar/correlatives/).

**One root, dozens of words** Reta Vortaro lists 23 words built on the root san-. Here are 15 of them – know a few prefixes and suffixes and you understand them without a dictionary.

## Common questions

### Does Esperanto grammar have exceptions?
Its inflection has none: every noun forms the plural with *-j*, and every verb uses the same six endings, including *esti* – "to be". What you still learn word by word is vocabulary, such as whether a verb takes an object.

### Does Esperanto have grammatical gender?
No. Nouns and adjectives do not change for gender. Female forms are made with the suffix *-in-*: *patro* – "father", *patrino* – "mother".

### Where is the official Esperanto grammar?
In the *Fundamento de Esperanto* (1905), which gives the 16 rules in five languages. The most complete modern description is PMEG by Bertilo Wennergren, free online.

## Sources

- [Fundamento de Esperanto: grammar, English version](https://www.akademio-de-esperanto.org/fundamento/gramatiko_angla.html) – Akademio de Esperanto
- [Akademia Vortaro: explanations and statistics](https://www.akademio-de-esperanto.org/akademia_vortaro/klarigoj.html) – 11 endings
- [PMEG – Plena Manlibro de Esperanta Gramatiko](https://bertilow.com/pmeg/) – Bertilo Wennergren, version 15.5 (2024)
- [Esperanto grammar](https://en.wikipedia.org/wiki/Esperanto_grammar) – Wikipedia