Hvorugir sandalarnir eru þægilegir, svo ég fer frekar í strigaskó.

Hvorugir means neither or not either one, and it is used when you are talking about two things.

So Hvorugir sandalarnir suggests neither of the two sandals / pairs of sandals under discussion is comfortable.

A useful contrast:

• Hvorugir sandalarnir eru þægilegir = Neither of the two sandals/pairs is comfortable
• Sandalarnir eru ekki þægilegir = The sandals are not comfortable

So hvorugir is more specific than just adding ekki.

Because it has to agree with sandalarnir in gender, number, and case.

Here, sandalarnir is:

• masculine
• plural
• nominative

So hvorugir also appears in the masculine plural nominative form: hvorugir.

This is very normal in Icelandic: determiners and adjectives change form to match the noun they belong to.

Yes, normally hvorugur is used for two alternatives.

That is one of the key things learners should notice. If there were more than two items, Icelandic would normally use a different structure, not hvorugir.

So this sentence sounds like the speaker has two sandal options in mind.

Because -nir is the definite article attached to the noun.

• sandalar = sandals
• sandalarnir = the sandals

Icelandic usually adds the definite article to the end of the noun rather than using a separate word like English the.

So sandalarnir literally means the sandals.

Because the subject is plural.

The subject is Hvorugir sandalarnir, which refers to more than one item grammatically, so the verb must also be plural:

• er = is (singular)
• eru = are (plural)

Even though English sometimes treats neither as singular, Icelandic here follows the plural noun phrase grammatically.

For the same reason as hvorugir: agreement.

Þægilegir is the form that matches sandalarnir, which is:

• masculine
• plural
• nominative

Because þægilegir is a predicate adjective after eru, it still agrees with the subject.

Compare:

• Sandalarnir eru þægilegir = masculine plural
• Skyrtan er þægileg = feminine singular
• Húsið er þægilegt = neuter singular

Because hvorugir already contains the negative idea.

So:

• Hvorugir sandalarnir eru þægilegir already means Neither of the sandals is comfortable

Adding ekki would usually be unnecessary or would change the structure.

This is similar to English: we say Neither is comfortable, not usually Neither is not comfortable.

Here svo means so, therefore, or as a result.

It connects the two clauses:

• Hvorugir sandalarnir eru þægilegir
• svo ég fer frekar í strigaskó

So the logic is:

The sandals aren’t a good option, so I’ll choose sneakers instead.

Frekar means rather, instead, or preferably.

In this sentence, it shows preference:

• ég fer frekar í strigaskó = I’d rather go in / wear sneakers
• more naturally in English: I’d rather wear sneakers instead

It often appears when comparing one option with another.

Yes, literally it looks like go into sneakers, but this is a normal Icelandic way to talk about putting on or choosing to wear clothing or footwear.

So:

• fara í skó can mean put on shoes / wear shoes
• fara í jakka can mean put on a jacket

In this sentence, ég fer frekar í strigaskó means something like:

• I’ll wear sneakers instead
• I’d rather put on sneakers

So it is idiomatic and very common.

Because after fara í meaning put on / go into, Icelandic uses the accusative, not the dative.

For strigaskór:

• nominative plural: strigaskór
• accusative plural: strigaskó
• dative plural: strigaskóm

So í strigaskó is correct here.

A useful rule of thumb:

• movement into something / putting something on often takes accusative
• being in something / wearing something already often takes dative

For example:

• Ég fer í strigaskó = I put on / choose sneakers
• Ég er í strigaskóm = I am wearing sneakers

Because here the speaker means sneakers in a general, indefinite sense, not the sneakers.

So:

• í strigaskó = in sneakers / wearing sneakers
• í strigaskóna would mean into the sneakers or put on the sneakers, referring to a specific pair already known in the conversation

The sentence is presenting sneakers as the preferred option, not pointing to a specific definite pair.