Esperanto uses the ti- correlatives to point to an identifiable person, thing, or type. Before a noun, tiu selects an individual—tiu libro “that book”—while tia selects a kind or quality—tia libro “that kind of book.” These forms are determiners, so they normally appear without la.
For explicit proximity, add the separate particle ĉi: ĉi tiu libro or tiu ĉi libro “this book.” Demonstratives express number and accusative case where their correlative family permits it; invariant la never does.
Tiu selects an identifiable individual
Use tiu before a singular noun when you point out or contrast one known individual.
Tiu seĝo estas libera.
That chair is free.
Mi preferas tiun seĝon apud la fenestro.
I prefer that chair by the window.
The minimal contrast shows subject tiu seĝo and object tiun seĝon. Tiu behaves adjective-like for agreement: when the noun takes accusative -n, so does the demonstrative.
Compare la and tiu:
La libro estas sur la tablo; tiu libro apud la lampo estas mia.
The book is on the table; that book beside the lamp is mine.
La libro assumes that context already makes the book identifiable. Tiu libro actively selects or points to one book, often in contrast with another. Both are definite, but the demonstrative adds deictic or contrastive force.
Number and case with tiu
The -u correlatives take plural -j and accusative -n. The demonstrative and its noun agree.
| Role | Singular | Plural |
|---|---|---|
| subject or non-accusative | tiu libro | tiuj libroj |
| accusative | tiun libron | tiujn librojn |
Tiuj ŝuoj aspektas komfortaj, sed mi ne aĉetos ilin hodiaŭ.
Those shoes look comfortable, but I will not buy them today.
Ĉu vi jam legis tiujn artikolojn? — Ne, mi konservis ilin por la trajno.
Have you read those articles yet? — No, I saved them for the train.
In tiujn artikolojn, -j marks several items and final -n marks the object. English “those” changes form for number but not object case; Esperanto marks both distinctions transparently.
Tiu can also stand without an expressed noun when context supplies it.
Mi prenos ĉi tiun tason; vi povas uzi tiun.
I will take this cup; you can use that one.
The final tiun stands for tiun tason and retains the object ending. If no context suggests a thing, a standalone -u word is often understood as referring to a person.
Ĉi marks proximity
The uninflected particle ĉi makes a ti- expression explicitly near the speaker or the current focus. It may stand before or after the correlative:
- ĉi tiu libro = tiu ĉi libro — this book
- ĉi tiuj libroj = tiuj ĉi libroj — these books
- ĉi tio = tio ĉi — this thing or situation
Ĉi tiu pordo estas ŝlosita; provu tiun pordon ĉe la angulo.
This door is locked; try that door at the corner.
Bonvolu subskribi ĉi tiujn du paĝojn.
Please sign these two pages.
Only tiu/tiujn changes for number and case. Ĉi never takes endings. In standard spelling, it remains a separate word: ĉi tiu, tiu ĉi, not ĉi-tiu or tiu-ĉi.
Actual distance is not always physical. A speaker can use ĉi tiu argumento for the argument currently under discussion and tiu argumento for one mentioned earlier or treated as more distant in discourse.
See ĉi as a proximity particle for its combinations beyond noun phrases.
Tiu versus tio
Tiu belongs to the -u series and can determine a noun or stand for an understood individual. Tio belongs to the -o series and stands independently for a thing, fact, or situation. It cannot directly modify a following noun.
Tiu propono ŝajnas praktika.
That proposal seems practical.
Tio ŝajnas praktika.
That seems practical.
The first points to an individual proposal; the second points to an understood thing or entire idea. English uses “that” in both structures, which makes tiu/tio a persistent transfer problem.
Mi ne komprenas tion, kion ŝi proponas.
I do not understand what she is proposing.
Here tion is an independent object referring to a proposition. No noun follows it.
Tiu versus tia: identity and type
Tiu answers “which individual?” Tia answers “what kind?” The distinction becomes especially clear in questions.
Kiun kafon vi volas? — Tiun kafon sur la supra breto.
Which coffee do you want? — That coffee on the top shelf.
Kian kafon vi volas? — Tian sen kafeino.
What kind of coffee do you want? — That kind, without caffeine.
Kiun/tiun identifies an item or selection. Kian/tian classifies by properties. Tia takes -j/-n like an adjective when agreement requires them.
Mi neniam antaŭe vidis tiajn grandajn fungojn.
I have never seen such large mushrooms before.
Although tia is formally a determiner in Esperanto grammar, it does not necessarily identify one individual. It determines a type. This is why definiteness and grammatical determiner status are related but not identical concepts.
Do not add la
Tiu and tia already occupy the determiner position. Neutral standard Esperanto says tiu domo, tia problemo, not la tiu domo or la tia problemo.
Tiu malnova ponto ne plu estas sekura.
That old bridge is no longer safe.
An adjective follows the determiner: tiu + malnova + ponto. More complex combinations such as tiu mia amiko occur with a special contrastive meaning, roughly “that friend of mine,” but they are not the neutral way to translate “my friend.” Basic production should use one determiner: tiu amiko or mia amiko. The advanced ordering is covered under determiner order and compatibility.
Common Mistakes
1. Using tio directly before a noun. A following noun requires the -u form.
❌ Tio libro apartenas al mi.
Incorrect — tio stands independently and cannot determine libro.
✅ Tiu libro apartenas al mi.
That book belongs to me.
2. Adding la before a demonstrative. Tiu already makes the phrase definite.
❌ Mi volas la tiun bluan tason.
Incorrect — la and tiun compete for the same determiner role.
✅ Mi volas tiun bluan tason.
I want that blue cup.
3. Forgetting plural agreement. Demonstrative and count noun both show -j.
❌ Tiu libroj estas venditaj.
Incorrect — several books require tiuj.
✅ Tiuj libroj estas venditaj.
Those books have been sold.
4. Omitting accusative -n from the demonstrative. Direct modifiers agree with the object noun.
❌ Mi aĉetis tiuj librojn hieraŭ.
Incorrect — tiuj must become tiujn.
✅ Mi aĉetis tiujn librojn hieraŭ.
I bought those books yesterday.
5. Hyphenating ĉi and tiu. They are separate words in standard orthography.
❌ Ĉi-tiu ŝlosilo ne funkcias.
Incorrect standard spelling — ĉi remains separate from tiu.
✅ Ĉi tiu ŝlosilo ne funkcias.
This key does not work.
Key Takeaways
- Tiu identifies an individual; tia identifies a type; tio stands independently for a thing or proposition.
- Tiu and tia take -j/-n in agreement with their noun.
- Add separate invariant ĉi for explicit proximity: ĉi tiu or tiu ĉi.
- Demonstratives replace neutral la rather than combining with it.
- La relies on shared context, while tiu adds pointing, selection, or contrast.
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Start learning Esperanto →Related Topics
- Tiu: The Demonstrative Individual CorrelativeA2 — Point out particular people or things with tiu, including its determiner, standalone, plural, accusative, and relative-pair uses.
- Tio: The Demonstrative Thing CorrelativeA2 — Use tio to point to an unnamed thing, fact, statement, or situation while distinguishing it from tiu and ĝi.
- Tia: The Demonstrative Kind Or Quality CorrelativeA2 — Use tia to point to a particular kind or quality, with the agreement and clause patterns that distinguish it from tiu and tiel.
- Ĉi as a Proximity ParticleA2 — Use the separate invariant particle ĉi with demonstratives to mark physical or discourse proximity, with correct spacing and agreement.
- Determiner Order and CompatibilityB2 — Which Esperanto determiners replace la, which combinations are possible, and how to order determination, quantity, and description.