Esperanto grammar: overview, endings and rules

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 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:

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.

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.
• 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.
• Word building. Prefixes and suffixes turn one root into many words: sana – "healthy", malsana – "ill", malsanulo – "patient", malsanulejo – "hospital". See word building.
• 45 correlatives. A 5 × 9 grid of question and answer words: kiu – "who", tiu – "that one", ĉiu – "everyone". See correlatives.

One root, dozens of wordsReta Vortaro lists 23 words built on san- alone. See how prefixes, suffixes and compounds grow one root into a family.Explore word families →

#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 – Akademio de Esperanto
• Akademia Vortaro: explanations and statistics – 11 endings
• PMEG – Plena Manlibro de Esperanta Gramatiko – Bertilo Wennergren, version 15.5 (2024)
• Esperanto grammar – Wikipedia