Soppan tinar i kylskåpet.

Because -n/-an is the definite ending in Swedish.

• soppa = soup
• soppan = the soup

So soppan means the soup, not just soup in general.

In Swedish, the is usually attached to the end of the noun instead of being a separate word.

So:

• soppan = the soup
• kylskåpet = the fridge

This is very normal in Swedish. English uses a separate article; Swedish often uses a suffix.

Because kylskåp is a neuter noun (ett word), not a common gender noun (en word).

The definite singular endings are often:

• common gender (en words): -en or -n
• neuter (ett words): -et or -t

So:

• ett kylskåp = a fridge
• kylskåpet = the fridge

Meanwhile:

• en soppa = a soup
• soppan = the soup

tinar is the present tense of the verb tina.

• tina = to thaw / defrost
• tinar = thaws / is thawing

In this sentence, it describes what is happening now or what the soup is in the process of doing.

Usually tina means to thaw or to defrost.

In this sentence, Soppan tinar means the soup is thawing.

A useful distinction:

• tina = become unfrozen / thaw
• smälta = melt

So if frozen soup is becoming unfrozen, tina is the natural choice.

Because Swedish present tense often covers both:

• simple present: thaws
• present progressive: is thawing

So Soppan tinar can mean:

• The soup thaws
• The soup is thawing

In everyday Swedish, you usually do not need a separate form for is thawing.

If you want to stress that something is in progress right now, Swedish can use expressions like håller på att, but that is not necessary here.

i means in, and it is used because the soup is inside the fridge.

• i kylskåpet = in the fridge

That matches English quite closely here.

Not if you mean inside the fridge.

• i kylskåpet = in the fridge
• på kylskåpet = on top of the fridge

So i is the correct preposition in this sentence.

Yes, but Swedish has V2 word order, which means the finite verb usually stays in the second position.

The normal order here is:

• Soppan tinar i kylskåpet.

You could also say:

• I kylskåpet tinar soppan.

That puts more focus on in the fridge, but notice that the verb tinar still comes second, and soppan moves after the verb.

You would not normally say:

• I kylskåpet soppan tinar. ❌

The dictionary forms are:

• soppa = soup
• tina = thaw / defrost
• kylskåp = fridge / refrigerator

The sentence uses inflected forms:

• soppan = the soup
• tinar = thaws / is thawing
• kylskåpet = the fridge

It is a compound noun:

• kyl- = cooling / chill
• skåp = cupboard / cabinet

So kylskåp literally means something like cooling cabinet, which is the Swedish word for fridge.

This is very common in Swedish: long nouns are often built by combining smaller words.

A rough guide for an English speaker is:

• Soppan ≈ SOHP-pan
• tinar ≈ TEE-nar
• i ≈ ee
• kylskåpet ≈ SHUUL-skoh-pet or KYUL-skoh-pet depending on how detailed you want to be about the ky sound

A few notes:

• i is pronounced like ee
• the y in kyl is a Swedish vowel that does not exist exactly in English
• stress is mainly on the first syllable of soppan, tinar, and kylskåpet

Not normally.

For ordinary everyday Swedish, tina is the natural verb for something becoming unfrozen.

• Soppan tinar i kylskåpet. = natural

avfrosta is more often used for defrosting something, especially appliances or freezer compartments, for example:

• Jag avfrostar frysen. = I am defrosting the freezer.

So for soup becoming unfrozen, tina is the better choice.