Pensillinn er góður fyrir hornin, en rúllan er betri fyrir stóra veggi.

Those endings are the suffixed definite article in Icelandic, equivalent to English the.

• pensill = brush

• pensillinn = the brush

• rúlla = roller
• rúllan = the roller

The exact form of the article changes depending on the noun’s gender and form. Here:

• pensill is masculine, so you get -inn
• rúlla is feminine, so you get -an

This is very common in Icelandic: instead of a separate word like English the, Icelandic usually attaches it to the noun.

Because the sentence is making a comparison:

• góður = good
• betri = better

So:

• Pensillinn er góður = The brush is good
• rúllan er betri = the roller is better

Also, betri is the comparative form of góður, and this comparison is a little irregular, just like English good → better.

A useful set to remember is:

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

So Icelandic behaves very similarly to English here.

Because góður has to agree with the subject, pensillinn.

In Icelandic, adjectives agree with the noun they describe in:

• gender
• number
• case

Here:

• pensillinn is masculine singular nominative
• so the adjective must also be masculine singular nominative
• that gives góður

Compare:

• pensillinn er góður = the brush is good
• rúllan er góð = the roller is good
• húsið er gott = the house is good

So the form changes depending on the noun.

Because góður is a predicate adjective after er and describes the subject of the clause, not the noun inside the prepositional phrase.

In:

• Pensillinn er góður fyrir hornin

the structure is:

• Pensillinn = subject
• er = is
• góður = adjective describing the subject
• fyrir hornin = for the corners

So the meaning is The brush is good for the corners, not The corners are good.

The same thing happens in the second clause:

• rúllan er betri fyrir stóra veggi

Here betri describes rúllan, not veggi.

Here fyrir means something like for or suitable for, and in this meaning it takes the accusative.

So:

• hornin is accusative plural
• stóra veggi is accusative plural

This is especially visible with veggir:

• nominative plural: veggir
• accusative plural: veggi

That is why you see veggi after fyrir, not veggir.

A key point for learners: Icelandic prepositions often require a specific case, and fyrir can take different cases depending on meaning. In this sentence, it is accusative.

Because stóra veggi is in the accusative plural, not the nominative plural.

The base noun is:

• veggur = wall

Plural forms include:

• nominative plural: veggir
• accusative plural: veggi

The adjective has to agree with the noun, so:

• nominative plural masculine: stórir veggir
• accusative plural masculine: stóra veggi

Since the phrase comes after fyrir, which takes the accusative here, the correct form is:

• fyrir stóra veggi

Because Icelandic, like English, does not always use the definite article. Here the meaning is more general:

• betri fyrir stóra veggi = better for large walls

It is talking about large walls as a type or general category, not a specific set already identified.

If you wanted to say the large walls, you would use the definite form, for example:

• fyrir stóru veggina

So the contrast is roughly:

• stóra veggi = large walls
• stóru veggina = the large walls

That is a meaning choice.

• hornin = the corners
• stóra veggi = large walls

In this kind of practical sentence, the corners often refers to the specific corners of the room or area being painted, so the definite form feels natural.

But large walls is more general: the roller is better for that kind of surface in general, not necessarily one already identified.

So the different article use reflects the speaker’s perspective:

• specific corners → hornin
• large walls in general → stóra veggi

The dictionary forms are:

• horn = corner
• veggur = wall

In the sentence, they appear in changed forms:

• hornin = the corners

  • from horn
  • plural definite
  • nominative and accusative plural look the same here

• veggi = walls

  • from veggur
  • accusative plural

So if you were looking these up in a dictionary, you would search for:

• horn
• veggur

Because comparative adjectives in Icelandic often do not show the same obvious gender differences that the basic adjective does in this position.

Compare:

• góður = masculine
• góð = feminine
• gott = neuter

But with the comparative:

• betri is used here with rúllan
• and you would also commonly see betri with masculine and neuter subjects in similar contexts

So for a learner, it is useful to remember that betri is much more uniform in form than góður.

En means but.

It connects two contrasting clauses:

• Pensillinn er góður fyrir hornin
• en rúllan er betri fyrir stóra veggi

So the sentence sets up a contrast:

• the brush is good for one job
• but the roller is better for another

This is a very common use of en in Icelandic.

In normal standard Icelandic, no—you would usually keep it.

So the natural sentence is:

• Pensillinn er góður fyrir hornin, en rúllan er betri fyrir stóra veggi.

Each clause has its own verb:

• pensillinn er
• rúllan er

English sometimes allows more omission in certain structures, but Icelandic normally keeps the verb here.

Yes, rúlla can mean roller, and in the context of painting it is understood as a paint roller.

If you want to be more explicit, Icelandic can also use a fuller expression such as:

• málningarrúlla = paint roller

But in a sentence like this, rúllan is completely natural because the painting context is clear from words like pensillinn, hornin, and veggir.

A rough learner-friendly guide:

• góður sounds approximately like GOH-thur

  • the ð is like the th in this, not thin

• rúllan sounds roughly like ROO-tlan or ROO-dlan depending on accent and how detailed you want to be

  • Icelandic ll often has a special pronunciation that is not like ordinary English ll

This is one reason these words may not sound exactly the way an English speaker expects from the spelling.

If you are just starting out, the most important thing is to recognize them when you hear them; perfect pronunciation can come later.