Hotelli on rauhallinen ja siisti.

Finnish does not have articles like the or a/an.

So hotelli can mean:

• the hotel
• a hotel

The exact meaning depends on context. In a standalone sentence like this, English often translates it as The hotel is peaceful and clean/tidy, but Finnish itself does not mark that distinction.

On is the third-person singular form of the verb olla, which means to be.

So:

• minä olen = I am
• sinä olet = you are
• hän on = he/she is
• hotelli on = the hotel is

In this sentence, on simply means is.

They are both adjectives, but they belong to different word types.

• rauhallinen = peaceful, calm
• siisti = clean, tidy, neat

Rauhallinen is a very common adjective type ending in -nen in the dictionary form.
Siisti is a different adjective type, with -i in the dictionary form.

So the difference is just because Finnish adjectives can have different basic forms, just like English adjectives can look different too: calm vs tidy.

After olla (to be), predicate adjectives usually appear in the nominative singular when the subject is singular.

Here:

• hotelli is singular
• so the adjectives are also singular predicate forms:
  • rauhallinen
  • siisti

This is similar to English:

• The hotel is quiet
• The room is clean

You do not need a special extra ending here just because the sentence uses is.

Yes, they often do, but the way agreement appears depends on the sentence structure.

In this sentence, the adjectives are predicate adjectives after on, and they match the singular subject:

• Hotelli on rauhallinen ja siisti.

If the subject were plural, the adjectives would also change:

• Hotellit ovat rauhallisia ja siistejä.
  = The hotels are peaceful and tidy.

So yes, agreement exists, but here you are seeing the singular predicate form.

Because both adjectives describe the same subject through the same verb.

So Finnish says:

• Hotelli on rauhallinen ja siisti.

Literally:

• Hotel is peaceful and tidy.

This works just like English:

• The hotel is peaceful and tidy.

You do not repeat on unless you want a different structure for emphasis.

Yes, Finnish word order is somewhat flexible, but Hotelli on rauhallinen ja siisti is the most neutral and natural order.

This order is:

• subject: hotelli
• verb: on
• adjectives: rauhallinen ja siisti

Other orders are possible for emphasis, for example:

• Rauhallinen ja siisti hotelli on.

But that sounds marked or unusual in normal conversation. For learners, the standard pattern is best:

• Hotelli on rauhallinen ja siisti.

This is a very common question.

• rauhallinen = peaceful, calm
• hiljainen = quiet, silent

A rauhallinen hotelli is a hotel with a calm, peaceful atmosphere.
A hiljainen hotelli focuses more on there being little noise.

Often these ideas overlap, but they are not identical. In this sentence, rauhallinen suggests a pleasant, calm environment rather than just silence.

Siisti can mean:

• clean
• tidy
• neat

In a sentence about a hotel, it often suggests the hotel is:

• clean
• well-kept
• neat in appearance

So it is a little broader than just not dirty. It can also suggest orderliness and a nice overall condition.

Ja means and.

It simply joins the two adjectives:

• rauhallinen ja siisti
• peaceful and tidy

It works very much like English and.

A simple learner-friendly pronunciation guide is:

Hotelli on rauhallinen ja siisti
HO-tel-li on RAU-hal-li-nen ya SII-sti

A few helpful points:

• Finnish stress is usually on the first syllable of each word.
• j in Finnish sounds like English y in yes.
  • so ja sounds like ya
• Double vowels are longer:
  • sii- in siisti is a long ii
• Double consonants are also pronounced longer:
  • ll in rauhallinen

It can mean either, depending on context.

Finnish olla does not make a strong built-in distinction like some other languages do between:

• a permanent characteristic
• a current state

So Hotelli on rauhallinen ja siisti can mean:

• the hotel is generally peaceful and tidy
• the hotel is peaceful and tidy right now

Usually context tells you which meaning is intended.