Tekjuárið er í skjalinu.

It is a compound noun:

• tekju- = a compound form related to tekjur (income, revenues)
• ár = year
• -ið = the neuter singular definite article, attached to the noun

So tekjuárið is literally the income year. Icelandic uses compounds very heavily, much more than English.

In Icelandic compounds, the first part of the word often appears in a special stem form rather than its basic dictionary form. Here, tekjur becomes tekju- before another noun.

This is very common in Icelandic, so learners get used to recognizing compound stems rather than expecting the full standalone word every time.

Because Icelandic usually adds the definite article to the end of the noun instead of putting it in front as a separate word.

For example:

• ár = year
• árið = the year

So tekjuárið means the income year, and you do not need a separate word like English the.

Tekjuárið is nominative singular neuter.

• nominative because it is the subject of the sentence
• singular because it refers to one income year
• neuter because tekjuár is a neuter noun

This matters because Icelandic endings change according to case, number, and gender.

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

Since tekjuárið is singular, the verb is singular too:

• tekjuárið er = the income year is
• if the subject were plural, you would use eru

For example: Tekjuárin eru ... = The income years are ...

Because í takes the dative when it means in a place or location.

Here, the meaning is static location: the income year is in the document. So you need the dative singular definite form of skjal:

• skjal = document
• skjalinu = in/to the document? here specifically in the document because of the dative after í

If you used skjalið, that would be the nominative/accusative definite form, which does not fit this sentence.

No. Í can take two different cases, depending on the meaning:

• dative for location: in
• accusative for motion/direction: into

A classic comparison is:

• Hann er í húsinu. = He is in the house.
• Hann fer í húsið. = He goes into the house.

In Tekjuárið er í skjalinu, it is location, so the dative is used.

Yes. That is completely normal in Icelandic.

English often uses two words where Icelandic prefers one compound word. So tekjuár is written as a single word, not as two separate words. Learning to spot compounds is a big part of learning Icelandic vocabulary.

Yes, to some extent. The neutral order here is:

Tekjuárið er í skjalinu.

But Icelandic often allows a different element to come first for emphasis or style, while keeping the verb in second position:

Í skjalinu er tekjuárið.

That is grammatical, but the original order is the most straightforward and neutral for a learner.

The letter ð is usually pronounced like the th in this, not like an English d.

So in tekjuárið, the ending -ið has a soft th sound. Two other useful pronunciation notes here are:

• j is pronounced like English y
• á is pronounced roughly like ow in now

So even if the exact Icelandic pronunciation takes practice, ð should be thought of as a soft th sound.