Graskerið er stórt.

In Icelandic, the definite article is usually added to the end of the noun as a suffix.

• grasker = pumpkin
• graskerið = the pumpkin

So instead of a separate word like English the, Icelandic often uses an ending.

This is very common:

• hús = house
• húsið = the house

Icelandic does have separate article-like words in some contexts, but for basic nouns like this, the suffixed article is the normal pattern.

Here, -ið is the definite article ending for a neuter singular noun in this form.

So:

• grasker = pumpkin
• graskerið = the pumpkin

The noun grasker is neuter, and that is why the article appears as -ið here.

This is not an ending you can use with every noun regardless of gender. The definite ending changes depending on the noun’s gender, number, and case.

Er is the present tense, 3rd person singular form of the verb vera (to be).

So:

• ég er = I am
• þú ert = you are
• hann / hún / það er = he / she / it is

Since graskerið is a singular thing, Icelandic uses er:

• Graskerið er stórt. = The pumpkin is big.

Because the adjective has to agree with the noun it describes.

Here, graskerið is:

• singular
• neuter
• the subject of the sentence

So the adjective must also be in the neuter singular form:

• stór = masculine/feminine base form in some contexts
• stórt = neuter singular

That is why you get:

• graskerið er stórt

Compare:

• bíllinn er stór = the car is big (masculine)
• bókin er stór = the book is big (feminine)
• graskerið er stórt = the pumpkin is big (neuter)

This is a very common question. The short answer is that stórt here is a predicate adjective, not an adjective placed directly before the noun.

In:

• Graskerið er stórt.

the adjective comes after er and describes the subject. In this position, Icelandic uses the form stórt.

But when the adjective comes directly before the noun, you get a different form:

• stóra graskerið = the big pumpkin

So:

• graskerið er stórt = the pumpkin is big
• stóra graskerið = the big pumpkin

This difference is very important in Icelandic.

Usually, you learn the gender of each noun as part of the word.

Dictionaries normally mark it, for example as n. for neuter.

In this sentence, there are also clues:

• the definite form graskerið
• the adjective form stórt

Both point to a neuter singular noun.

Unfortunately, you often cannot reliably guess noun gender just from meaning. So it is best to learn nouns together with gender and, if possible, with the definite form too:

• grasker (n.)
• graskerið

That makes agreement much easier later.

It is in the nominative case, because it is the subject of the sentence.

In:

• Graskerið er stórt.

graskerið is the thing that is big, so it is the subject.

The adjective stórt also matches that nominative subject.

One small complication: for many neuter nouns, the nominative and accusative singular forms are the same, so the form graskerið does not visibly change. But grammatically, in this sentence, it is nominative.

Yes. This is the most basic and natural word order:

• Subject + verb + complement
• Graskerið er stórt.

That said, Icelandic word order can vary more than English word order, especially for emphasis or in questions.

For example:

• Er graskerið stórt? = Is the pumpkin big?

So the sentence you have is the standard neutral statement form.

You usually move the verb to the front:

• Er graskerið stórt? = Is the pumpkin big?

This is very common in Icelandic yes/no questions.

So compare:

• Graskerið er stórt. = statement
• Er graskerið stórt? = question

You would need to change the noun, the verb, and the adjective so they agree.

Singular:

• Graskerið er stórt. = The pumpkin is big.

Plural:

• Graskerin eru stór. = The pumpkins are big.

Changes:

• graskerið → graskerin
• er → eru
• stórt → stór

This shows how important agreement is in Icelandic.

The ð in Icelandic is usually like the th in this, but often softer than an English speaker expects.

A rough pronunciation of graskerið would be something like:

• GRAHS-keh-rith

That is only an approximation, not an exact phonetic spelling.

A few helpful points:

• a in gras is not the same as English a in cat
• r is rolled or tapped
• ð is a soft voiced sound, like th in this

If you are learning pronunciation, it is best to listen to native audio, because Icelandic spelling is fairly consistent, but some sounds are still hard to guess from English alone.