Í ljósi þess að framtalsfresturinn nálgast lesum við um álagninguna.

Í ljósi þess að is a fixed expression meaning in light of the fact that, considering that, or since in a formal style.

It is built from:

• í = in
• ljósi = the dative singular of ljós here in the idiomatic sense light
• þess = of that / of it in the genitive
• að = that

So literally it is something like in the light of that that..., but in natural English you should understand it as in light of the fact that...

This is a very common formal connector in Icelandic.

Because the phrase í ljósi normally takes a genitive complement.

So:

• ljós → genitive idea after this expression
• það becomes þess in the genitive singular

That is why Icelandic says í ljósi þess að...

You can think of it as a chunk you learn as a whole:

• í ljósi þess að = in light of the fact that

Even if the literal grammar feels unusual at first, it is best to memorize the whole phrase.

This is because Icelandic follows the verb-second rule in main clauses.

The sentence begins with the adverbial phrase:

• Í ljósi þess að framtalsfresturinn nálgast

When something other than the subject comes first in a main clause, the finite verb still has to stay in the second position, so the subject comes after it:

• Í ljósi þess að ... lesum við um álagninguna.

Compare:

• Við lesum um álagninguna. = We read / are reading about the assessment.
• Í ljósi þess að ... lesum við um álagninguna. = In light of the fact that ..., we read / are reading about the assessment.

So this inversion is normal and expected.

Framtalsfresturinn is a compound noun:

• framtal = tax return
• frestur = deadline, extension, time limit

Together:

• framtalsfrestur = tax return deadline / filing deadline

Then the definite article is added to the end:

• framtalsfrestur = a tax return deadline
• framtalsfresturinn = the tax return deadline

The -s- in the middle comes from the first part of the compound, where framtal appears in a linking/genitive form:

• framtal → framtals-

This kind of compound formation is extremely common in Icelandic.

That ending is the suffixed definite article, one of the most important features of Icelandic nouns.

Instead of a separate word for the, Icelandic usually adds the article to the noun itself.

So:

• frestur = a deadline
• fresturinn = the deadline

And with the full compound:

• framtalsfrestur = a tax return deadline
• framtalsfresturinn = the tax return deadline

In this sentence it is in the nominative singular because it is the subject of nálgast.

Here nálgast means approach, draw near, or be getting closer.

So:

• framtalsfresturinn nálgast = the filing deadline is approaching

The -st ending often marks a middle voice verb in Icelandic. These verbs do not always translate as reflexive verbs in English. In many cases, the -st form simply has its own meaning and should be learned as a normal dictionary form.

So here:

• nálga can mean bring closer
• nálgast means approach / come near

In this sentence, nálgast is just the natural verb to use for a deadline coming closer.

Yes, lesum is the 1st person plural present tense of lesa:

• ég les = I read
• við lesum = we read / we are reading

Icelandic present tense often covers both:

• a simple present meaning
• a present progressive meaning

So lesum við can mean either:

• we read
• we are reading

The correct English translation depends on context. If the situation is about what you are doing now, English often prefers are reading.

Because að introduces a subordinate clause, and Icelandic word order there is usually more straightforward:

• að framtalsfresturinn nálgast = that the filing deadline is approaching

Inside this clause, the subject framtalsfresturinn comes before the verb nálgast.

So the sentence contains:

1. a subordinate clause after í ljósi þess að
   • framtalsfresturinn nálgast
2. the main clause
   • lesum við um álagninguna

This contrast is very common in Icelandic:

• subordinate clause: subject before verb
• main clause: verb-second

The preposition um takes the accusative in this meaning of about/concerning.

So:

• álagning = assessment / imposition / tax assessment
• accusative singular definite: álagninguna

That is why the sentence says:

• um álagninguna = about the assessment / about the tax assessment

A useful pattern to remember is:

• að lesa um eitthvað = to read about something

with um + accusative.

Álagning is a formal noun whose meaning depends on context. In general it refers to an imposition, levying, or assessment of something. In tax-related language, it often means tax assessment.

Since the sentence also contains framtalsfresturinn (the filing deadline), the tax context is strong, so álagninguna most likely means something like:

• the tax assessment
• the levy
• the assessed charges/taxes

This is a good example of a word whose most natural English translation depends on the specific context.

Yes, but the tone would change.

• Í ljósi þess að is more formal and written.
• þar sem can mean since / as in many contexts.
• af því að often means because and is common in everyday language.

So these are not always perfect replacements, but they can express a similar idea.

For example:

• Í ljósi þess að framtalsfresturinn nálgast...
  In light of the fact that the filing deadline is approaching...

This sounds more official or administrative than a simpler everyday connector.

The structure is:

• [Adverbial clause] + [finite verb] + [subject] + [rest]

More specifically:

• Í ljósi þess að framtalsfresturinn nálgast = introductory adverbial clause
• lesum = finite verb
• við = subject
• um álagninguna = prepositional phrase

So the full pattern is:

• In light of the fact that X, read we about Y
• which in natural English becomes:
• In light of the fact that X, we are reading about Y

This is a very typical Icelandic sentence pattern after an introductory phrase.