Barnið fær að leika sér úti ef veðrið er gott.

Barn means child in the indefinite sense, while barnið means the child.

The ending -ið is the definite article attached to the noun. Icelandic usually adds the as a suffix instead of using a separate word.

So:

• barn = a child / child
• barnið = the child

Also, barn is a neuter noun, which matters for agreement elsewhere in the sentence.

The dictionary form is fá, which often means to get, to receive, or in some contexts to be allowed to.

Fær is the 3rd person singular present tense form, used here because the subject is barnið = the child.

A few useful forms are:

• ég fæ = I get / I am allowed to
• þú færð = you get / you are allowed to
• hann/hún/það fær = he/she/it gets / is allowed to

So barnið fær means the child gets / is allowed to.

Yes, very often fá að + infinitive means get to do something or be allowed to do something.

In this sentence, fær að leika sér means something like:

• gets to play
• is allowed to play

So this is a very common Icelandic structure:

• fá að borða = get to eat
• fá að fara = get to go
• fá að leika sér = get to play

Even though fá often means receive, in this pattern it expresses permission or opportunity.

Here að is the infinitive marker, like English to in to play.

So:

• leika = play
• að leika = to play

After fá in the sense of get to / be allowed to, Icelandic normally uses að + infinitive:

• fær að fara = gets to go
• fær að sofa = gets to sleep
• fær að leika sér = gets to play

So að is there because leika is in the infinitive.

Because to play in the sense of children playing is very commonly expressed as leika sér in Icelandic.

Literally, it is something like play oneself or amuse oneself, but you should usually understand it simply as play.

Compare:

• leika sér = play, have fun
• leika can also mean play in other senses, such as play a role, act, or play something

So in a sentence about a child playing outside, leika sér is the natural expression.

Sér is a reflexive pronoun. It refers back to the subject, here barnið.

In leika sér, the reflexive pronoun is part of the standard expression. English does not usually translate it directly, so although Icelandic says something like play oneself, natural English is just play.

Grammatically:

• sér is the reflexive form used for himself / herself / itself / themselves in certain contexts
• here it is in the dative case

So barnið fær að leika sér literally contains a reflexive element, but in normal English you just say the child gets to play.

Because the expression leika sér requires the reflexive pronoun in the dative.

This is something learners often just need to memorize as part of the verb phrase:

• leika sér = to play

Many Icelandic verbs and fixed expressions govern a particular case. In this one, the reflexive pronoun is dative, so you get:

• ég leik mér
• þú leikur þér
• hann/hún/það leikur sér

So the best way to learn it is as one unit: leika sér.

Úti means outside or outdoors.

In this sentence it works as an adverb, describing where the child plays.

So:

• leika sér úti = play outside / play outdoors

A useful contrast is:

• út = out, outward movement
• úti = outside, outdoors, in an outside location

So if the idea is location rather than movement, úti is the right choice here.

Veður means weather, while veðrið means the weather.

The ending -ið is again the definite article attached to a neuter noun.

So:

• veður = weather
• veðrið = the weather

In Icelandic, using the definite form in sentences like this is very natural. Veðrið er gott is a common way to say the weather is good.

Because gott agrees with veðrið, which is neuter singular nominative.

The adjective góður changes form depending on gender, number, and case:

• góður = masculine
• góð = feminine
• gott = neuter

Since veðrið is neuter singular, the adjective must also be neuter singular:

• veðrið er gott = the weather is good

This kind of agreement is very important in Icelandic.

Both are in the nominative case because each is the subject of its own clause.

• Barnið is the subject of the main clause: Barnið fær ...
• veðrið is the subject of the subordinate clause: ef veðrið er gott

So the sentence has two clauses:

1. main clause: Barnið fær að leika sér úti
2. subordinate clause: ef veðrið er gott

And each clause has its own nominative subject.

This is a subordinate clause introduced by ef, which means if.

The word order here is quite straightforward:

• ef = if
• veðrið = the weather
• er = is
• gott = good

So it follows a normal subject-verb-complement pattern.

A useful thing to know is that the if-clause can also come first:

• Ef veðrið er gott, fær barnið að leika sér úti.

When the subordinate clause comes first, the main clause still follows Icelandic verb-second word order, so fær comes before barnið.

Yes. Icelandic allows some flexibility, and this sentence can very naturally be reordered as:

• Ef veðrið er gott, fær barnið að leika sér úti.

This means the same thing.

The main difference is emphasis:

• Barnið fær að leika sér úti ef veðrið er gott.
  starts with the child
• Ef veðrið er gott, fær barnið að leika sér úti.
  starts with the condition

This is a good example of how Icelandic word order is flexible, but still follows certain rules like verb-second in the main clause.

Ef is the normal word for if when introducing a condition.

So:

• ef veðrið er gott = if the weather is good
• ef þú kemur = if you come
• ef ég hef tíma = if I have time

It is a very common conjunction and works much like English if.