Tuli paloi koko yön.

Because tuli can be two different words:

• tuli = fire (a noun)
• tuli = came (the past tense of tulla, to come)

In Tuli paloi koko yön, the next word is paloi (burned / was burning), so tuli must be the noun fire.
So the structure is:

• tuli = the fire
• paloi = burned

Context usually makes the meaning clear in Finnish.

Paloi is the past tense of the verb palaa.

Here:

• palaa = to burn
• paloi = burned / was burning

So Tuli paloi means The fire burned or The fire was burning.

A useful extra note: palaa can also mean to return, but in this sentence, with tuli (fire), it clearly means to burn.

Because Finnish often uses a special case form for the length of time that something lasts.

• yö = night
• yön = a case form used here in the expression koko yön = all night / the whole night

So:

• koko yö would sound incomplete or unnatural here
• koko yön is the normal way to say for the whole night

This is a common pattern in Finnish with time expressions.

Koko means whole or entire.

So:

• koko yön = the whole night / all night

In the sentence, it tells you how long the fire burned.

You can think of the sentence like this:

• Tuli = fire
• paloi = burned
• koko yön = all night

So the fire burned for the entire night.

Finnish does not have articles like English a, an, and the.

So tuli can mean:

• fire
• a fire
• the fire

Which one sounds best depends on context and translation style.
In this sentence, English usually says The fire burned all night, but Finnish does not need a separate word for the.

Yes. This is a very normal, neutral Finnish sentence order:

• Tuli = subject
• paloi = verb
• koko yön = time expression

So it follows the common pattern:

• Subject + Verb + Time expression

Finnish word order is more flexible than English, though. For example:

• Koko yön tuli paloi.

This is possible, but it puts more emphasis on all night.
The original sentence is the most neutral and straightforward version.

It can correspond to both in English.

Finnish does not separate these in the same way English does.
So paloi can mean:

• burned
• was burning

In this sentence, English most naturally says:

• The fire burned all night
• or The fire was burning all night

Both match the Finnish well.

The dictionary forms are:

• tuli = fire
• palaa = to burn
• koko = whole, entire
• yö = night

The sentence uses these forms:

• tuli stays tuli
• palaa becomes paloi in the past tense
• yö becomes yön in this time expression

So learning the dictionary forms helps you recognize what is changing.

For many English speakers, yö is one of the trickiest parts.

Roughly:

• y is pronounced like the German ü or the French u
• ö is like the German ö or the French eu in some words

So yö contains two front rounded vowels in sequence.

A rough approximation is something like "yurn" or "ew-uhn", but neither is exact.
The important thing is that y is not like English y in yes.

If you know IPA, yön is approximately [yøn].

Yes. Tuli is a general word for fire, so it could refer to:

• a campfire
• a fireplace fire
• a house fire
• any other fire

The sentence itself does not specify.
You only know that the fire burned all night. The exact kind of fire would come from the wider context.