La kafejo ne estas tiel silenta kiel la biblioteko.

Tiel ... kiel is the Esperanto pattern for as ... as in comparisons of equality.

So:

• tiel silenta kiel = as quiet as

Because the sentence has ne, the full idea becomes:

• ne estas tiel silenta kiel ... = is not as quiet as ...

This is a very common structure in Esperanto:

• Ŝi estas tiel alta kiel sia frato. = She is as tall as her brother.
• Li ne estas tiel rapida kiel vi. = He is not as fast as you.

In Esperanto, ne normally goes directly before the word it negates. Here it negates the whole verb phrase:

• La kafejo ne estas ... = The café is not ...

That is the most natural placement.

If you put ne somewhere else, the emphasis can change or the sentence may sound less normal to a learner’s ear. So as a basic rule, with a sentence like this, put ne before the verb:

• Mi ne scias. = I do not know.
• Ŝi ne venos. = She will not come.

Because silenta is an adjective.

In Esperanto:

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

So:

• silenta = quiet, silent
• silento = silence
• silente = quietly

In this sentence, silenta describes la kafejo, so it must be an adjective.

Also, adjectives in Esperanto agree with the noun they describe in number and case. Here:

• kafejo is singular
• there is no accusative

So the adjective stays in the basic form:

• silenta

Because they are nouns.

In Esperanto, all basic singular nouns end in -o:

• kafejo = café
• biblioteko = library
• domo = house
• urbo = city

This is one of the most regular features of Esperanto and makes it easier to identify parts of speech.

The suffix -ej- usually means place for or place associated with something.

So:

• kaf- = coffee
• -ej- = place
• -o = noun

Together:

• kafejo = a coffee place, café

Other useful examples:

• lernejo = school
  (lern- learn + -ej- place)
• kuirejo = kitchen
  (kuir- cook + -ej- place)
• dormejo = dormitory / sleeping place
  (dorm- sleep + -ej- place)

This is a very productive Esperanto suffix.

La is the definite article, meaning the.

It is used here because both nouns are definite:

• la kafejo = the café
• la biblioteko = the library

Just like in English, if you are talking about specific places, you often use the.

A useful point: Esperanto has only one definite article, la, and it never changes for gender, number, or case.

So it is always:

• la libro
• la libroj
• la virino
• la domojn

Yes. A very close equivalent is:

• La kafejo estas malpli silenta ol la biblioteko.

This means:

• The café is less quiet than the library.

That is logically very close to:

• La kafejo ne estas tiel silenta kiel la biblioteko.
• The café is not as quiet as the library.

Both are natural, but the structure is slightly different:

• tiel ... kiel = as ... as
• pli ... ol = more ... than
• malpli ... ol = less ... than

So:

• tiel silenta kiel = as quiet as
• pli silenta ol = quieter than
• malpli silenta ol = less quiet than

Because Esperanto uses different comparison words for different patterns:

• tiel ... kiel = as ... as
• pli/malpli ... ol = more/less ... than

So in this sentence, since the pattern is tiel ... kiel, kiel is the correct word.

Compare:

• Li estas tiel forta kiel mi. = He is as strong as I am.
• Li estas pli forta ol mi. = He is stronger than I am.

A learner should memorize these as set comparison patterns.

Yes, it is the same Esperanto word, but the meaning depends on context.

Kiel can appear in several common uses, such as:

• Kiel vi fartas? = How are you?
• Li agas kiel instruisto. = He acts like a teacher.
• tiel granda kiel = as big as

So in your sentence, kiel is part of the comparison pattern tiel ... kiel, meaning as.

This is normal in Esperanto: one word can have a few related uses, and the sentence pattern tells you which one is meant.

Because there is no direct object here.

The sentence is built with estas:

• La kafejo = subject
• estas = is
• silenta = predicate adjective
• kiel la biblioteko = comparison phrase

In Esperanto, the accusative -n is mainly used for a direct object or for motion toward something. Neither of those is happening here.

So:

• La kafejo is the subject, not an object.
• la biblioteko is part of the comparison, not a direct object.
• silenta is a predicate adjective, not an object.

That is why no -n appears.

Esperanto word order is fairly flexible, but this sentence in its current order is the most neutral and natural:

• La kafejo ne estas tiel silenta kiel la biblioteko.

Because Esperanto marks grammar clearly with endings, you can move things around more than in English, especially for emphasis. But for a learner, it is best to keep the ordinary order:

subject + ne + verb + comparison

So this sentence is an excellent standard model.

A simple English-friendly guide is:

• tiel ≈ TEE-el
• kiel ≈ KEE-el

In careful pronunciation, the vowels are both heard:

• ti-el
• ki-el

Esperanto spelling is very regular, so pronunciation is much more predictable than in English.

A rough full pronunciation of the sentence is:

• lah kah-FEY-oh neh ES-tahs TEE-el see-LEN-tah KEE-el lah bee-blee-oh-TEH-koh

The exact accent falls on the second-to-last syllable of each word:

• kaFEjo
• EStas
• siLENta
• biblioTEko

That stress rule is always consistent in Esperanto.