Sumir vilja frekar te en kaffi.

Sumir means some or, more naturally here, some people.

In this sentence it stands on its own without a noun after it, so Icelandic is effectively saying some [people] prefer tea to coffee. English does the same thing in sentences like Some prefer tea to coffee.

Because sumir is the masculine plural nominative form.

When Icelandic refers to a group of people in a general or unspecified way, the masculine plural is often used as the default, especially if the group is mixed or the gender is not stated.

So:

• sumir = some people, in a general sense
• sumar could be used for an all-female group, depending on context

This does not automatically mean the sentence is talking only about men.

Yes. The basic meaning of vilja is to want, but in this kind of structure it can be used to express preference.

So the sentence is literally close to:

• Some want rather tea than coffee

But natural English is:

• Some prefer tea to coffee
• Some would rather have tea than coffee

So vilja + frekar gives the sense of would rather / prefer.

This is the key comparison pattern in the sentence.

• frekar = rather / more readily
• en = than

So:

• frekar te en kaffi = tea rather than coffee

You can think of the whole structure as:

• X vilja frekar A en B = X prefer A to B / X would rather have A than B

It is a very common and natural way to express preference in Icelandic.

Because Icelandic builds this idea differently from English.

English often says:

• prefer tea to coffee

But Icelandic here uses a comparison structure:

• frekar ... en ... = rather ... than ...

So instead of to, Icelandic uses en, meaning than.

A very literal comparison would be:

• English: prefer tea to coffee
• Icelandic: would rather have tea than coffee

Both mean the same thing, but the grammar is different.

They function as the direct objects of vilja, so they are in the accusative.

However, you do not see any obvious change here because these noun forms look the same in this sentence:

• kaffi is a neuter noun whose nominative and accusative are the same in the singular
• te also appears unchanged here

So even though the grammar involves the accusative, the words themselves do not visibly change in this example.

Because the sentence is talking about tea and coffee in general, not specific tea or specific coffee.

That is very natural in Icelandic, just as it is in English:

• Some prefer tea to coffee
• not necessarily the tea or the coffee

Both te and kaffi are being used as general mass nouns, so no article is needed.

Because this is normal Icelandic main-clause word order.

A helpful way to see it is:

• Sumir = subject
• vilja = finite verb
• frekar = adverb
• te en kaffi = compared objects

Icelandic main clauses usually follow the verb-second pattern, meaning the finite verb comes very early in the clause. After that, adverbs such as frekar often come right after the verb.

So Sumir vilja frekar te en kaffi sounds natural and standard.

Yes. This sentence is already natural, but Icelandic has more than one way to express preference.

For example, you may also meet constructions with:

• heldur ... en ...
• or verbs that mean choose / prefer in certain contexts

But vilja frekar te en kaffi is a good, straightforward, everyday way to say it.

For a learner, the important pattern to remember is:

• vilja frekar X en Y = prefer X to Y / would rather have X than Y