Gönguskórnir hennar eru nýir, en stígurinn að fossinum er blautur eftir rigninguna.

Because -nir is the definite article attached to a masculine plural noun.

• gönguskór = hiking shoes
• gönguskórnir = the hiking shoes

Icelandic usually attaches the to the end of the noun instead of using a separate word like English the.

So Gönguskórnir hennar literally looks like the hiking-shoes her, but naturally means her hiking shoes.

That is very common in Icelandic. Possessive words like hennar (her) often come after the noun, especially when the noun is definite.

So:

• gönguskórnir hennar = her hiking shoes
• literally: the hiking shoes of her

This word order is normal and natural in Icelandic, even though it feels different from English.

It is a compound noun:

• göngu- = walking, hiking
• skór = shoes

So gönguskór means walking shoes / hiking shoes.

Then the definite ending is added:

• gönguskór = hiking shoes
• gönguskórnir = the hiking shoes

Compound words are extremely common in Icelandic, so learning to spot the parts is very useful.

Because nýir has to agree with Gönguskórnir.

Here is what matters:

• gönguskórnir is masculine
• plural
• nominative (it is the subject)

So the adjective must match that, and the correct form is:

• nýir = new, masculine plural nominative

Also, this adjective is predicative: it comes after the verb eru (are), not directly before the noun. That is why you get:

• Gönguskórnir hennar eru nýir = Her hiking shoes are new

Because the verb must match the subject in number.

• Gönguskórnir hennar = plural subject, so eru = are
• stígurinn = singular subject, so er = is

So:

• Gönguskórnir hennar eru nýir = Her hiking shoes are new
• stígurinn ... er blautur = The path ... is wet

Again, this is the attached definite article.

• stígur = path, trail
• stígurinn = the path, the trail

For this masculine singular noun, the definite ending is -inn in the nominative singular.

So stígurinn að fossinum means the path to the waterfall.

Because the preposition að normally takes the dative case, and fossinum is the dative singular definite form of foss (waterfall).

Forms of foss here are:

• foss = waterfall
• fossinn = the waterfall
• fossi = to/at a waterfall (dative indefinite)
• fossinum = to/at the waterfall (dative definite)

So:

• að fossinum = to the waterfall

This is a very common Icelandic pattern: the preposition decides the case.

Here að means something like to in the path to the waterfall.

It often expresses direction toward something or relation to something, and it takes the dative.

So:

• stígurinn að fossinum = the path to the waterfall

This does not mean the same as the infinitive marker að in forms like að lesa (to read). Icelandic að can have different functions depending on context.

Because blautur must agree with stígurinn.

• stígurinn is masculine
• singular
• nominative

So the adjective must also be masculine singular nominative:

• blautur = wet

Compare:

• masculine singular: blautur
• feminine singular: blaut
• neuter singular: blautt

So stígurinn er blautur = the path is wet.

Here eftir means after, and in this meaning it takes the accusative.

So:

• rigning = rain
• rigninguna = the rain (accusative singular definite)

That gives:

• eftir rigninguna = after the rain

This is another important Icelandic rule: many prepositions require a specific case, and you have to learn which one each preposition uses in each meaning.

No. The basic dictionary form is usually the indefinite nominative singular, which here is:

• rigning = rain

Then you can form:

• rigningin = the rain (nominative)
• rigninguna = the rain (accusative)

In this sentence, the preposition eftir requires the accusative, so you see rigninguna, not rigningin.

Because in this sentence the adjectives are not directly modifying the nouns inside the noun phrase. They come after the verb and describe the subject.

This is called a predicative adjective:

• Gönguskórnir hennar eru nýir = Her hiking shoes are new
• stígurinn ... er blautur = The path is wet

If the adjective were placed directly before the noun, that would be a different structure.

So here Icelandic is doing the same general thing as English:

• The shoes are new
• The path is wet

The only big difference is that Icelandic adjectives show more visible agreement in gender, number, and case.

Yes. In this sentence, en simply means but:

• ..., en ... = ..., but ...

It connects two clauses:

• Her hiking shoes are new,
• but the path to the waterfall is wet after the rain.

It is a very common coordinating conjunction.

The sentence is built from two main clauses joined by en:

1. Gönguskórnir hennar eru nýir

   • subject: Gönguskórnir hennar
   • verb: eru
   • complement: nýir

2. stígurinn að fossinum er blautur eftir rigninguna

   • subject: stígurinn að fossinum
   • verb: er
   • complement: blautur
   • adverbial phrase: eftir rigninguna

So the overall pattern is very close to English: subject + verb + complement, with extra prepositional phrases added where needed.

A few common ones:

• Göngu-: the ö is not like English o
• skórnir: ó is a long vowel sound
• stígurinn: í is pronounced like ee in see
• fossinum: double ss is pronounced as a long s
• rigninguna: this can feel long and heavy because of the consonant cluster gn

Also, Icelandic stress usually falls on the first syllable of the word:

• GÖNGUskórnir
• STÍGurinn
• RIGNinguna

That first-syllable stress is one of the most helpful pronunciation habits to learn early.