Ĉi tiu premio apartenas al ŝi.

In Esperanto, tiu means that one / that, and ĉi is a little particle that brings the meaning closer, like here or this. So:

• tiu = that
• ĉi tiu = this

You may also see tiu ĉi, which means exactly the same thing. Both are correct:

• ĉi tiu premio
• tiu ĉi premio

Both mean this prize.

Because premio is the subject of the sentence. In Esperanto, the subject normally does not take -n.

Here:

• Ĉi tiu premio = the thing being talked about
• apartenas = belongs
• al ŝi = to her

You use -n mainly for a direct object, but aparteni does not take a direct object here. Instead, it uses al.

Because the verb aparteni is used with the preposition al.

So Esperanto says:

• aparteni al iu = to belong to someone

That means the owner is expressed with al, not with a direct object ending.

So:

• apartenas al ŝi = belongs to her

Not:

• apartenas ŝin ❌

Also note:

• ŝi = she
• ŝin = her (direct object form)

Since this is not a direct object, ŝi stays without -n.

Apartenas comes from the verb aparteni, which means to belong.

The ending -as shows present tense, so:

• aparteni = to belong
• apartenas = belongs / is belonging

So Ĉi tiu premio apartenas al ŝi literally means:

• This prize belongs to her.

In Esperanto, verbs always have regular endings:

• -as = present
• -is = past
• -os = future
• -us = conditional
• -u = command / volitive
• -i = infinitive

So apartenas is present tense: belongs.

Examples:

• Ĉi tiu premio apartenis al ŝi. = This prize belonged to her.
• Ĉi tiu premio apartenos al ŝi. = This prize will belong to her.

Because ŝi is a pronoun, while ŝia is a possessive adjective.

Compare:

• al ŝi = to her
• ŝia premio = her prize

In this sentence, Esperanto uses the pattern aparteni al iu, so it needs al ŝi.

You could express a similar idea differently with ŝia:

• Ĉi tiu estas ŝia premio. = This is her prize.

That is grammatical, but it is a different sentence structure.

Yes. That means This is her prize.

It is very close in meaning, but the grammar is different:

• Ĉi tiu premio apartenas al ŝi. = This prize belongs to her.
• Ĉi tiu estas ŝia premio. = This is her prize.

The first uses the verb aparteni.
The second uses esti plus a possessive adjective.

Both are natural, but they are built differently.

Because tiu is used for a specific identifiable thing, while tio usually means that thing in a more general, stand-alone way.

Here premio is a noun, and tiu works like a determiner before it:

• tiu premio = that prize
• ĉi tiu premio = this prize

But tio normally stands alone:

• Tio estas premio. = That is a prize.

So before premio, you want ĉi tiu, not ĉi tio.

No. Both orders are possible:

• ĉi tiu premio
• tiu ĉi premio

Both mean this prize.

However, ĉi tiu is very common and often feels more natural to learners because it matches the idea of this more directly.

Yes, Esperanto word order is fairly flexible, because grammar is shown by endings and prepositions.

The normal order is:

• Ĉi tiu premio apartenas al ŝi.

But you could also say:

• Al ŝi apartenas ĉi tiu premio.

This can sound more emphatic, like It is to her that this prize belongs.

Still, the original order is the most straightforward and neutral.

Premio is a noun. The ending -o shows that.

In Esperanto:

• -o = noun
• -a = adjective
• -e = adverb

So:

• premio = prize, award
• premia would be an adjective related to a prize
• premie would be an adverbial form, if needed in a suitable context

In the sentence, premio is the noun being described by ĉi tiu.

A native English speaker often wonders about these sounds:

• ŝ sounds like English sh
• ĉ sounds like English ch

So:

• ŝi sounds like she
• ĉi sounds roughly like chee

Also:

• tiu is roughly TEE-oo
• premio is roughly preh-MEE-o
• apartenas is roughly a-par-TE-nas

Esperanto pronunciation is very regular, so once you know the letters, you can usually pronounce words reliably.

Yes, that is a very good idea.

Many Esperanto verbs naturally go with a certain preposition, and aparteni commonly goes with al:

• aparteni al iu = to belong to someone
• aparteni al io = to belong to something

So it is useful to learn it as a unit:

• aparteni al

That will help you avoid mistakes like trying to use a direct object after it.