En aŭtuno la parko ŝajnas pli trankvila ol en somero.

En aŭtuno means in autumn / in the autumn.

In Esperanto, en is the normal preposition for being in a time period or place:

• en somero = in summer
• en vintro = in winter
• en la parko = in the park

So En aŭtuno sets the time frame for the whole sentence: during autumn, the park seems calmer.

You could also hear seasonal adverb forms like aŭtune and somere, but en aŭtuno is very straightforward and common.

Esperanto uses la only when something is definite.

• la parko = the park, a specific park
• aŭtuno = autumn, used here as a general season, so no article is needed

This is similar to English, where we often say:

• in autumn
• in summer

not necessarily in the autumn unless we want a more specific style or emphasis.

So:

• en aŭtuno = in autumn
• la parko = the park

Ŝajnas is the present-tense form of ŝajni, meaning to seem.

Esperanto verb endings are regular:

• -as = present
• -is = past
• -os = future
• -us = conditional
• -i = infinitive

So:

• ŝajni = to seem
• ŝajnas = seems

The subject is la parko, which is singular, but in Esperanto the verb does not change according to person or number. So:

• mi ŝajnas would be wrong because it means I seem, but grammatically the verb form is still ŝajnas
• la parko ŝajnas
• la parkoj ŝajnas

The verb stays the same.

Because trankvila is an adjective describing la parko.

After verbs like ŝajni (to seem), Esperanto usually uses an adjective if it describes the subject:

• La parko ŝajnas trankvila = The park seems calm

Here, trankvila agrees with parko:

• parko = singular noun
• trankvila = singular adjective

If you used trankvile, that would be an adverb, meaning something like calmly, which does not fit well here. The park is not seeming calmly; rather, the park itself seems calm.

This is the Esperanto pattern for comparisons:

• pli = more
• ol = than

So:

• pli trankvila = more calm / calmer
• pli trankvila ol en somero = calmer than in summer

This works with adjectives and adverbs:

• pli granda ol = bigger than
• pli rapide ol = more quickly than

So the full comparison here is:

• in autumn, the park seems more calm than it does in summer

Because ol only means than. It does not include the meaning of in.

The comparison is really between two time settings:

• en aŭtuno = in autumn
• en somero = in summer

So Esperanto keeps both phrases complete:

• En aŭtuno la parko ŝajnas pli trankvila ol en somero.

Literally, that is:

• In autumn, the park seems calmer than in summer.

This is normal and natural.

Yes. That is also correct and very natural.

Esperanto often uses -e adverb forms for times and seasons:

• aŭtune = in autumn
• somere = in summer
• tage = by day / during the day
• nokte = at night

So these two are both good:

• En aŭtuno la parko ŝajnas pli trankvila ol en somero.
• Aŭtune la parko ŝajnas pli trankvila ol somere.

The version with en + noun may feel a bit more literal to an English-speaking learner, while the adverbial form is compact and elegant.

Yes, Esperanto word order is fairly flexible.

This sentence begins with En aŭtuno to emphasize the time:

• En aŭtuno la parko ŝajnas pli trankvila ol en somero.

But you could also say:

• La parko ŝajnas pli trankvila en aŭtuno ol en somero.

Both are understandable and correct. The original version simply puts the seasonal contrast first, which sounds natural.

Esperanto often moves elements around for emphasis, as long as the grammar stays clear.

Because it is not a direct object here.

The accusative -n is used mainly for:

1. direct objects
2. motion toward something in some cases

In this sentence:

• la parko is the subject
• ŝajnas is the verb
• trankvila is a predicate adjective describing the subject

So no accusative is needed:

• La parko ŝajnas trankvila.

If the noun were plural, the adjective would match in number:

• La parkoj ŝajnas trankvilaj.

But still no -n, unless there were a special reason.

Ŝajni means to seem / to appear. It links the subject to a description, much like esti (to be), but with the meaning of appearance rather than certainty.

Compare:

• La parko estas trankvila. = The park is calm.
• La parko ŝajnas trankvila. = The park seems calm.

So ŝajni is a linking verb. That is why the adjective trankvila describes the subject la parko.

In aŭtuno, the aŭ is a diphthong, roughly like ow in English cow, though pronunciation may vary slightly depending on accent.

A rough guide:

• aŭ ≈ ow
• tu = too
• no = no

So aŭtuno is approximately ow-TOO-no.

Also, Esperanto stress normally falls on the second-to-last syllable, so:

• aŭ-TU-no

That same aŭ sound appears in words like:

• ankaŭ = also
• aŭ = or

Ŝ is pronounced like English sh.

So:

• ŝajnas sounds roughly like SHY-nahs

A few useful Esperanto letter comparisons:

• ŝ = sh
• ĉ = ch
• ĵ = the s in measure
• ĝ = the j in judge

So ŝajni begins with a clear sh sound:

• ŝajni = to seem
• ŝajnas = seems