Skilningurinn verður betri þegar útskýringin er skýr.

Those endings are the suffixed definite article in Icelandic. Instead of using a separate word like English the, Icelandic often attaches the article to the noun.

• skilningur = understanding

• skilningurinn = the understanding

• útskýring = explanation
• útskýringin = the explanation

The exact form of the ending depends on the noun’s gender, number, and case.

In this sentence:

• skilningurinn is masculine singular nominative definite
• útskýringin is feminine singular nominative definite

So the sentence is talking about the understanding and the explanation, not just understanding or explanation in general.

verður is the present tense of verða, which often means become.

So:

• er = is
• verður = becomes / will be

In this sentence, Skilningurinn verður betri means The understanding becomes better or Understanding gets better.

That is slightly different from Skilningurinn er betri, which would mean The understanding is better.
Using verður emphasizes a change: understanding improves as a result of the explanation being clear.

betri is the comparative form of góður (good).

The three common degrees are:

• góður = good
• betri = better
• bestur = best

So Skilningurinn verður betri literally means The understanding becomes better.

In Icelandic, adjectives usually agree with the noun they describe, but comparative forms like betri are often the same across several genders in the nominative singular, so you do not see as much variation here as you do with many basic adjective forms.

Because skýr agrees with útskýringin, which is a feminine singular noun.

• skýr = clear, in the form that matches a feminine singular noun here
• skýrt would be used with a neuter singular noun in the same kind of structure

So:

• útskýringin er skýr = the explanation is clear

This is an example of adjective agreement: the adjective changes form to match the noun in gender, number, and case.

Here þegar means when.

So:

• þegar útskýringin er skýr = when the explanation is clear

In many contexts, þegar introduces a time clause, just like English when.
In this sentence, it has a slightly general meaning: when the explanation is clear, understanding improves.

Depending on context, English might translate the whole sentence more naturally as:

• Understanding is better when the explanation is clear
• Understanding improves when the explanation is clear

Both main nouns are in the nominative case, because they are the subjects of their clauses.

• Skilningurinn is the subject of verður
• útskýringin is the subject of er

So the structure is:

• Skilningurinn verður betri
  • The understanding becomes better
• þegar útskýringin er skýr
  • when the explanation is clear

This is a useful sentence because it shows a very straightforward subject + verb + complement pattern in both clauses.

Yes. If the subordinate clause comes first, Icelandic uses normal verb-second word order in the main clause.

You can say:

• Skilningurinn verður betri þegar útskýringin er skýr.

But you can also say:

• Þegar útskýringin er skýr, verður skilningurinn betri.

Notice what happens in the second version:

• the þegar clause comes first
• then the verb verður comes before skilningurinn

This is a very common Icelandic pattern. English learners often expect skilningurinn verður to stay together, but in Icelandic the finite verb typically comes second in the main clause.

Without the definite article, it would be more general:

• Skilningur verður betri þegar útskýring er skýr.

But that sounds less natural in many contexts. Icelandic often prefers the definite form in statements like this, especially when talking about something understood in a general-but-specific way.

The original:

• Skilningurinn verður betri þegar útskýringin er skýr.

can sound like a general truth, even though both nouns are formally definite.

This is not always exactly the same as English usage, so learners should not expect Icelandic definiteness to line up perfectly with English the every time.

The letter ð in Icelandic is usually like the th in English this, not like the th in thin.

So in verður:

• ð is voiced, like English th in that

A rough learner-friendly pronunciation guide for the sentence might be:

• Skilningurinn verður betri þegar útskýringin er skýr

with:

• ð in verður sounding like th in this
• þ in þegar sounding like th in thin
• ý and ú being long rounded vowels that do not match English exactly

It is better not to rely too heavily on English spelling approximations, but the ð / þ contrast is especially important:

• ð = voiced th
• þ = voiceless th

Yes, skilningur is a very common word for understanding, both in the sense of:

• mental comprehension
• sympathetic understanding, depending on context

In this sentence, it clearly means comprehension or understanding of something explained.

So:

• Skilningurinn verður betri means something like understanding improves or comprehension becomes better

That is a natural use of skilningur in Icelandic.

It can work as either, depending on context, but most naturally it sounds like a general truth:

• Understanding improves when the explanation is clear.

Even though the nouns are definite in Icelandic, the sentence can still express a broad idea rather than referring to one specific explanation in one specific moment.

That is something English speakers should get used to: Icelandic can use definite nouns in ways that still feel fairly general in translation.