Húsið er of stórt.

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

• hús = house
• húsið = the house

So -ið here is the neuter singular definite ending.

Hús is a neuter noun.

In this sentence, you can see that from two clues:

• the definite form is húsið
• the adjective is stórt, which is the neuter singular form of stór

So the whole phrase agrees in gender and number:

• húsið = neuter singular definite noun
• stórt = neuter singular adjective

Because adjectives in Icelandic must agree with the noun they describe.

Since húsið is neuter singular, the adjective must also be in the neuter singular form:

• masculine: stór
• feminine: stór
• neuter: stórt

So:

• húsið er stórt = the house is big

The -t ending is a very common neuter singular adjective ending.

Even after er (is), Icelandic adjectives still agree with the subject.

So in:

• Húsið er stórt

the adjective stórt describes húsið, so it must match it in gender and number.

This is similar to English The house is big, except Icelandic shows agreement more clearly in the adjective form.

No. Icelandic of is a completely different word.

In this sentence, of means too in the sense of excessively:

• of stórt = too big

It is not related to English of.

This is a very common thing that confuses English speakers because the spelling looks familiar.

No. In this sentence, of means excessively, not also.

Compare:

• of stórt = too big
• líka = also / too

So if you want English too meaning also, you usually need a different Icelandic word, such as líka.

Er is the present tense of vera, the verb to be.

So:

• vera = to be
• er = is

In this sentence:

• Húsið er of stórt = The house is too big

No, this is a very normal Icelandic sentence pattern:

• Húsið = subject
• er = verb
• of stórt = complement

So the structure is basically:

subject + is + too + adjective

Very close to English word order in this case.

A simple learner-friendly approximation is:

HOO-see-th er of stort

A few pronunciation notes:

• ú in Húsið is like oo
• ð is like the th in this, though in some positions it can sound weaker
• ó in stórt is like a long o
• rt in stórt may sound sharper than an English speaker expects

You do not need perfect pronunciation right away, but it helps to notice that ð is a real Icelandic letter, not just decoration.

Because Icelandic often expresses the by adding an ending to the noun.

So instead of:

• the house

Icelandic often uses:

• húsið

This is one of the first big differences English speakers notice. Icelandic can use a separate demonstrative word in some contexts, but the ordinary definite article is usually attached to the noun.

Without of, the sentence would simply mean:

• Húsið er stórt = The house is big

Adding of changes the meaning to:

• Húsið er of stórt = The house is too big

So of adds the idea of more than is acceptable, suitable, or wanted.

Yes, if the noun has a different gender, the adjective form may change too.

For example, bíll (car) is masculine, so you would say:

• Bíllinn er of stór.

But with the neuter noun hús, you say:

• Húsið er of stórt.

So the adjective changes to match the noun:

• masculine: stór
• feminine: stór
• neuter: stórt