Stelpan grípur boltann auðveldlega.

Because stelpan means the girl, not just girl.

In Icelandic, the definite article (the) is usually attached to the end of the noun instead of being a separate word.

• stelpa = girl
• stelpan = the girl

So the -n is the definite article, and the extra vowel is part of how the form is built.

Boltann means the ball in the form required by the sentence.

The verb grípa (to catch / grab) takes a direct object, and that object is normally in the accusative case. So bolti changes form.

Here is the pattern:

• bolti = a ball / dictionary form
• boltann = the ball in the accusative singular

So:

• Stelpan grípur boltann = The girl catches the ball

Both the case ending and the attached definite article are showing up in boltann.

The basic dictionary form is grípa, meaning to catch, grab, or seize.

Grípur is the present tense, third person singular form:

• ég gríp = I catch
• þú grípur = you catch
• hann/hún/það grípur = he/she/it catches

Since stelpan is a third-person singular subject (the girl), the verb is grípur.

Because Icelandic usually expresses the as a suffix attached to the noun.

So instead of saying something like:

• the girl
• the ball

with a separate article, Icelandic commonly says:

• stelpan
• boltann

This is one of the first big differences English speakers notice.

Auðveldlega is an adverb, and it means easily.

It describes how the girl catches the ball.

So:

• Stelpan = the girl
• grípur = catches
• boltann = the ball
• auðveldlega = easily

In other words, it modifies the verb grípur.

In this sentence, auðveldlega comes after the object:

• Stelpan grípur boltann auðveldlega.

That is a perfectly natural placement.

Icelandic word order is somewhat flexible, but not random. In a simple neutral sentence, this order is very normal:

• Subject + Verb + Object + Adverb

You may also encounter adverbs in other positions depending on emphasis, style, or sentence structure, but the version here is straightforward and natural for learners.

You can tell from both meaning and case/form.

• Stelpan is in the nominative form, which is the usual case for the subject.
• Boltann is in the accusative form, which is the usual case for the direct object of grípa.

So the sentence means:

• The girl = the one doing the action
• the ball = the thing being caught

This is especially important in Icelandic, because endings often tell you what role a word plays in the sentence.

Yes, grípa is traditionally treated as a strong verb, and that matters more when you learn other tenses.

In the present tense here, you just need:

• grípa → grípur

But in past forms, strong verbs often change their vowel, so they do not behave like the most regular weak verbs. That is something to keep in mind as you continue learning.

For this sentence, though, the key point is simply that grípur is the correct present singular form.

A rough learner-friendly guide is:

• grípur ≈ GREE-pur

A few notes:

• í is a long ee sound.
• The u in Icelandic does not sound exactly like English u. It is more rounded and different from the English vowel in put or cup.
• The r is typically trilled or tapped.

So an English approximation helps, but the real Icelandic pronunciation is a bit different from standard English sounds.

A rough approximation is:

• auðveldlega ≈ OYTH-veld-leh-ga or OYTH-veld-leh-ga

A few important points:

• au is usually like oy in boy
• ð is like the th in this (though pronunciation can vary slightly by context)
• g in Icelandic does not always sound like English g in all positions, so exact pronunciation may differ from the rough guide

It is a long word, so learners often benefit from breaking it into parts:

• auð
• veld
• lega

Yes. Icelandic present tense often covers both:

• The girl catches the ball easily
• The girl is catching the ball easily

Like many languages, Icelandic does not have a separate obligatory progressive form like English is catching in ordinary usage. Context usually tells you whether the meaning is habitual, general, or happening right now.

They look different because Icelandic nouns belong to different declension patterns, and their endings change depending on:

• gender
• number
• case
• whether they are definite

So even though both mean the ..., they do not add the article in exactly the same way.

For example:

• stelpa is a feminine noun
• bolti is a masculine noun

And boltann is also in the accusative, because it is the object.

So the different endings are normal and expected. Icelandic does not have one single universal ending for the.

A very literal breakdown is:

• Stelpan = the girl
• grípur = catches / is catching
• boltann = the ball (object form)
• auðveldlega = easily

So the structure is:

The girl catches the ball easily.

That is also close to the natural English translation, which makes this a nice beginner sentence even though the Icelandic grammar contains several important features like case and suffixed articles.