An Esperanto noun phrase is built around a head noun, normally recognizable by -o. Other elements identify, count, describe, or locate that head: la tri grandaj domoj ĉe la rivero means “the three large houses by the river.” The head domoj controls the phrase’s basic number and meaning.
The transparent endings let the phrase carry its role across several words. If those houses become a direct object, the agreeing adjective and noun receive -n: Mi vidas la tri grandajn domojn. English relies heavily on position; Esperanto also writes number and case onto the relevant phrase members.
The basic pattern
A useful neutral template is:
determiner + quantity + adjective(s) + head noun + postmodifier(s)
Not every phrase uses every slot.
| Part | Example | Function |
|---|---|---|
| determiner | la, tiu, mia | identifies or anchors the referent |
| quantity | tri, kelkaj, multaj | states number or amount |
| adjective | grandaj, renovigitaj | describes or classifies the head |
| head noun | domoj | names the central referent |
| postmodifier | ĉe la rivero | adds a relation, location, or clause |
La tri grandaj domoj ĉe la rivero estas malnovaj.
The three large houses by the river are old.
Mi vidas la tri grandajn domojn ĉe la rivero.
I see the three large houses by the river.
The minimal change from subject to object appears on grandaj/domoj → grandajn/domojn. The prepositional phrase ĉe la rivero does not copy that accusative because it has its own internal structure.
The head noun
The head supplies the central category. In ruĝa aŭto, the phrase denotes an aŭto, not a color. In skatolo da teo, the grammatical head is skatolo, while da teo states what quantity or contents the box represents.
Ruĝa aŭto haltis antaŭ la hotelo.
A red car stopped in front of the hotel.
Sur la breto restas unu skatolo da teo.
One box of tea remains on the shelf.
An ordinary noun head uses the productive -o citation form and may add -j and -n. The root remains available for related forms: ĝarden-o “garden,” ĝarden-a “garden-related,” ĝarden-i “to garden.” That analysis helps identify which element heads a phrase rather than treating every word as an unanalyzable block.
For the category itself, see nouns and the -o ending.
Determiners: do not stack them like English articles
The article la marks a referent as identifiable in context. Esperanto has no indefinite article: bare libro can mean “a book,” while la libro means “the book.” Possessives such as mia and demonstratives such as tiu already determine the phrase, so do not add la before an overt noun that has one of them.
Libro kuŝas sur la seĝo; la libro apartenas al Ĝoja.
A book is lying on the chair; the book belongs to Ĝoja.
Mia nova biciklo jam bezonas riparon.
My new bicycle already needs a repair.
Ĉu tiu malgranda valizo estas via?
Is that small suitcase yours?
More complex combinations such as tiu mia ideo are attested with a special contrastive effect, but simple possession is mia ideo. La mia can mean “mine” when the noun is omitted; before an overt noun, however, la mia ideo is not the standard form. Determiner compatibility is treated under determiner order and compatibility.
Quantities and number
Cardinal numerals such as du and tri do not take -j or -n, but a count noun denoting multiple items does take -j. Adjectival quantity words such as multaj behave like adjectives and agree.
Du junaj muzikistoj prezentos la programon.
Two young musicians will present the program.
Ni invitis multajn junajn muzikistojn.
We invited many young musicians.
In the second sentence, multajn, junajn, and muzikistojn all show plural and accusative. The numeral in du junaj muzikistoj stays du, while junaj muzikistoj is plural.
Substance phrases use a quantity head plus da: litro da lakto, tri kilogramoj da pomoj. The form after da names what fills the quantity and does not take an accusative merely because the entire phrase is an object; the case ending appears on the quantity head.
Ŝi aĉetis du litrojn da lakto.
She bought two liters of milk.
Countability follows the intended Esperanto meaning, not an English noun's grammar. A substance noun can name an undivided amount, while a plural can present distinct varieties or servings:
Mi aĉetis kafon kaj sukeron por la oficejo.
I bought coffee and sugar for the office.
Ni mendis tri kafojn kaj petis kelkajn informojn pri la trajnoj.
We ordered three coffees and asked for some information about the trains.
Here tri kafojn means three servings of coffee. Informoj is also an ordinary Esperanto plural even though English usually treats “information” as a mass noun. The communicative unit—not a mechanically copied English count/mass label—determines whether -j is appropriate.
Direct adjectives and agreement
An adjective directly describing a noun normally carries the same plural -j and accusative -n as that noun. The neutral order places the adjective before the head, but postposed adjectives are possible for rhythm, contrast, or style.
La nova instruisto salutis la novajn studentojn.
The new teacher greeted the new students.
Ni serĉas solvon simplan sed fidindan.
We are looking for a solution that is simple but reliable. (postposed adjectives for contrastive rhythm)
The postposed adjectives simplan and fidindan still agree with object solvon. Position does not cancel the relation. At A1, adjective-before-noun is the clearest production default; later pages explain scope and stylistic order.
Postmodifiers: prepositional phrases and relative clauses
A prepositional phrase after the noun can express possession, source, location, purpose, or another relation:
- la libro de Ana — Ana’s book / the book by Ana, depending on context
- la trajno al Berlino — the train to Berlin
- la tablo apud la fenestro — the table by the window
La ŝlosilo de la malantaŭa pordo malaperis.
The key to the back door disappeared.
The adjective malantaŭa belongs to pordo, not ŝlosilo. If the entire outer phrase becomes an object, only its head and direct modifiers receive the outer accusative; an ordinary preposition governs its own complement.
Mi trovis la ŝlosilon de la malantaŭa pordo.
I found the key to the back door.
A relative clause can also identify or describe the head:
La najbaro, kiu loĝas supre, helpis nin.
The neighbor who lives upstairs helped us.
The relative word has its role inside its own clause. The commas here mark supplementary information; restrictive and nonrestrictive relatives receive detailed treatment elsewhere.
Word order: flexible, not structureless
Esperanto permits adjectives before or after nouns and can move whole phrases for information structure. It does not permit random scrambling that obscures which modifier belongs where. Keep semantically close material close, repeat agreement, and use the neutral template when no special emphasis is intended.
Sur la tablo mi lasis la dosieron kun la ruĝa etikedo.
On the table I left the file with the red label.
The fronted location sur la tablo is outside the object noun phrase la dosieron kun la ruĝa etikedo. Case and prepositions make those boundaries recoverable.
Common Mistakes
1. Adding an English-style indefinite article. Esperanto uses a bare noun phrase.
❌ A hundo bojas ekstere.
Incorrect — Esperanto has no indefinite article equivalent to English a/an.
✅ Hundo bojas ekstere.
A dog is barking outside.
2. Using a bare root where the phrase needs a noun. The head requires the noun ending -o.
❌ Mia frat laboras hejme.
Incorrect — frat- is a root, not a complete noun.
✅ Mia frato laboras hejme.
My brother works at home.
3. Forgetting adjective agreement. Direct modifiers copy number and case.
❌ Mi vidis la grandaj domojn.
Incorrect — the adjective lacks accusative -n.
✅ Mi vidis la grandajn domojn.
I saw the large houses.
4. Putting accusative -n after da on the substance noun. Mark the quantity head.
❌ Ni aĉetis tri kilogramoj da pomojn.
Incorrect — the outer object case belongs on kilogramoj, while pomoj follows da.
✅ Ni aĉetis tri kilogramojn da pomoj.
We bought three kilograms of apples.
5. Letting an embedded modifier agree with the wrong head. Analyze the phrase in layers.
❌ Ni malfermis la pordon de la malnovan domon.
Incorrect — domo follows de and does not receive the outer accusative.
✅ Ni malfermis la pordon de la malnova domo.
We opened the door of the old house.
Key Takeaways
- The -o word is the noun-phrase head; other elements identify, count, describe, or relate it.
- A useful neutral order is determiner + quantity + adjective + noun + postmodifier.
- Esperanto has la but no indefinite article; possessives and demonstratives normally determine without la.
- Direct adjectives agree with the head in plural -j and accusative -n.
- Prepositional phrases and relative clauses have their own internal grammar; analyze nested phrases one layer at a time.
Related Topics
- Nouns and the -O EndingA1 — Build Esperanto nouns with -o, then add -j for plural and -n for accusative while respecting meaning and countability.
- Singular and Plural NounsA1 — How Esperanto builds singular, plural, and accusative noun forms from a stable root using -o, -j, and -n.
- Determiner Order and CompatibilityB2 — Which Esperanto determiners replace la, which combinations are possible, and how to order determination, quantity, and description.
- Adjective Agreement in NumberA1 — Learn why Esperanto adjectives take -j when they describe plural people or things, in both noun phrases and predicates.
- Adjective Agreement in the AccusativeA1 — Learn when Esperanto adjectives copy the accusative -n, how -ajn is built, and why predicative adjectives normally remain without -n.