Bæturnar eru háar.

Because Icelandic usually puts the definite article onto the end of the noun instead of using a separate word like English the.

• bætur = compensation / damages / benefits in the plural
• bæturnar = the compensation / the damages / the benefits

Here, -nar is the definite ending for this plural feminine form.

So:

• bætur = indefinite
• bæturnar = definite

It is plural.

The basic singular noun is bót, but in this meaning Icelandic very often uses the plural form bætur. Depending on context, it can mean things like compensation, damages, or benefits.

That is why the sentence uses plural grammar throughout:

• bæturnar = plural noun
• eru = plural verb
• háar = plural adjective

Because the subject is plural.

The verb is from að vera = to be.

Present tense:

• ég er = I am
• þú ert = you are
• hann / hún / það er = he / she / it is
• við erum = we are
• þið eruð = you are
• þeir / þær / þau eru = they are

Since bæturnar is plural, Icelandic uses eru:

• Bæturnar eru háar. = The benefits/compensation are high.

Because adjectives in Icelandic must agree with the noun they describe in gender, number, and case.

The noun here is:

• bæturnar
• feminine
• plural
• nominative

So the adjective hár = high has to match that form:

• masculine singular: hár
• feminine singular: há
• neuter singular: hátt
• feminine plural nominative: háar

That is why the sentence says:

• Bæturnar eru háar

and not hár, há, or hátt.

It is nominative.

In this sentence, bæturnar is the subject:

• Bæturnar = the benefits / the compensation
• eru = are
• háar = high

Subjects are normally in the nominative case, and the predicate adjective also matches that nominative form.

So both the noun phrase and the adjective are in forms that fit a nominative plural feminine subject.

No, here it means high in the sense of large in amount.

The adjective hár can mean high or tall, depending on context. With something like bætur—money, damages, compensation, benefits—it means high rather than tall.

So the sentence means something like:

• The compensation is high
• The damages are high
• The benefits are high

depending on the context already given.

They are:

• bót = singular dictionary form of the noun
• að vera = to be
• hár = high / tall

The sentence uses inflected forms of those dictionary entries:

• bót → bætur → bæturnar
• að vera → eru
• hár → háar

This is very typical in Icelandic: the form you see in a sentence is often not the dictionary form.

Because Icelandic usually expresses the by attaching it to the noun.

So instead of English:

• the benefits

Icelandic usually says:

• bæturnar

This is one of the first big differences English speakers notice. Icelandic can use a separate form like hinn / hin / hið in some situations, but the normal everyday pattern is the suffixed article, as in bæturnar.

Yes, but Bæturnar eru háar is the normal, neutral order.

This is the basic pattern:

• Subject + verb + adjective

A different order can be used for emphasis or style, but it would sound less neutral. For a learner, Bæturnar eru háar is the form to remember and use first.

You would remove the definite ending from the noun:

• Bætur eru háar.

That means Benefits/compensation are high in a more indefinite or general sense.

Compare:

• Bæturnar eru háar. = The benefits/compensation are high.
• Bætur eru háar. = Benefits/compensation are high.

A rough learner-friendly guide is:

• Bæturnar ≈ BYE-tur-nar
• eru ≈ EH-ru
• háar ≈ HOW-ar

A few useful notes:

• æ is usually pronounced like the vowel in English eye
• á is usually like ow in now
• The r is pronounced clearly
• Icelandic pronunciation is more precise than English spelling suggests, so listening to native audio is especially helpful

A rough full pronunciation guide could be:

• BYE-tur-nar EH-ru HOW-ar

That is only approximate, but it helps as a starting point.