La biblioteko estas tute senpaga.

In Esperanto, -o is the normal noun ending. So biblioteko is a noun meaning library.

This is one of the most basic patterns in the language:

• libro = book
• domo = house
• instruisto = teacher
• biblioteko = library

Seeing -o immediately tells you the word is a noun.

La is the Esperanto definite article, meaning the.

So:

• la biblioteko = the library
• biblioteko by itself can mean a library or just library, depending on context

Esperanto has no separate word for a/an. That is often surprising for English speakers.

Estas means is / am / are in the present tense.

A very learner-friendly feature of Esperanto is that verbs do not change according to the subject. So:

• mi estas = I am
• vi estas = you are
• li estas = he is
• ŝi estas = she is
• ĝi estas = it is
• ili estas = they are

It is always estas in the present tense.

Because tute is an adverb, and here it means completely or entirely.

Compare:

• tuta = whole, entire, complete (adjective)
• tute = completely, entirely (adverb)

In this sentence, tute modifies senpaga, not biblioteko. It tells you the library is completely free.

So:

• tute senpaga = completely free

If you said tuta biblioteko, that would mean the whole library.

Senpaga is built from parts:

• sen = without
• pag = pay / payment
• -a = adjective ending

So senpaga literally means without payment, which naturally becomes free in English.

This kind of word-building is very common in Esperanto, and it helps a lot once you get used to it.

Related words:

• pagi = to pay
• pago = payment
• senpage = free of charge, for free (adverb)
• senpaga = free, free of charge (adjective)

Because it is an adjective.

In Esperanto:

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

Here, senpaga describes la biblioteko, so it must be an adjective:

• La biblioteko estas senpaga. = The library is free.

Even after a verb like estas, Esperanto still uses an adjective to describe the noun.

Yes. Adjectives agree with the nouns they describe in number and case.

In this sentence, both words are singular and not in the accusative, so they stay in their basic forms:

• la biblioteko
• senpaga

If the noun were plural, the adjective would also become plural:

• La bibliotekoj estas senpagaj. = The libraries are free.

So agreement is important, even when the adjective comes after estas.

Yes, Esperanto word order is fairly flexible, although some orders sound more natural than others.

The normal order here is:

• La biblioteko estas tute senpaga.

You could also say:

• Tute senpaga estas la biblioteko.

That is grammatical, but it sounds more marked or emphatic, like Completely free is the library. In ordinary speech and writing, the original order is the most natural.

Yes. Senpaga already means free or free of charge. Adding tute strengthens it:

• senpaga = free
• tute senpaga = completely free, totally free

This can emphasize that there is no charge at all.

Not in this sentence.

• senpaga is an adjective, so it describes the library: The library is free.
• senpage is an adverb, so it describes how something happens: for free, free of charge

So:

• La biblioteko estas senpaga. = The library is free.
• Oni povas uzi la bibliotekon senpage. = One can use the library for free.

That adjective/adverb distinction is important.

It is pronounced roughly bee-blee-o-TEH-ko.

A few useful pronunciation points:

• each vowel is pronounced clearly
• stress in Esperanto normally falls on the second-to-last syllable
• so biblioteko is stressed on te

Syllables:

• bi-bli-o-te-ko

That regular stress rule is one of the nice things about Esperanto.