Morgunninn er kaldur.

Morgunninn means the morning.

It breaks down like this:

• morgunn = morning
• -inn = the suffixed definite article, roughly the

So Icelandic often puts the onto the end of the noun instead of using a separate word the way English does.

In this sentence, morgunninn is the nominative singular definite form: the morning.

Because the base noun already ends in -nn:

• morgunn = morning

Then the definite ending is added:

• -inn = the

So the result is morgunninn.

This looks a bit heavy at first, but it is normal in Icelandic spelling. Also, different cases can change the shape of the word. For example, the accusative form is morguninn, with one less n in the middle.

Because Icelandic usually uses a suffixed definite article.

So instead of:

• English: the morning

you often get:

• Icelandic: morgunn-inn

This is one of the first big differences English speakers notice. Icelandic can also use a separate article-like word (hinn / hin / hið) in some contexts, but the normal everyday way is the ending attached to the noun.

Er means is.

It is the 3rd person singular present tense of the verb vera (to be).

A few useful present-tense forms are:

• ég er = I am
• þú ert = you are
• hann / hún / það er = he / she / it is
• við erum = we are
• þið eruð = you are
• þeir / þær / þau eru = they are

Since morgunninn is singular, Icelandic uses er.

Because Icelandic adjectives must agree with the noun they describe.

They change for:

• gender
• number
• case

Here, morgunn is:

• masculine
• singular
• nominative

So the adjective must also be masculine singular nominative:

• kaldur = cold

Compare:

• kaldur = masculine
• köld = feminine
• kalt = neuter

So Morgunninn er kaldur uses the correct masculine form.

That is a very common question.

The short answer is: because kaldur here is a predicate adjective, not an adjective directly in front of the noun.

In:

• Morgunninn er kaldur. = The morning is cold.

the adjective comes after er and describes the subject through the verb to be. In this position, Icelandic uses the regular agreeing form kaldur.

But when the adjective is directly attached to a definite noun, you often get the weak form instead:

• kaldi morgunninn = the cold morning

So:

• Morgunninn er kaldur = full sentence, The morning is cold
• kaldi morgunninn = noun phrase, the cold morning

Morgunninn is in the nominative case, because it is the subject of the sentence.

After vera (to be), the predicate adjective also appears in the nominative, so:

• morgunninn = nominative masculine singular
• kaldur = nominative masculine singular

So yes, they match.

Yes, it matters grammatically.

In Icelandic, every noun has a grammatical gender:

• masculine
• feminine
• neuter

Morgunn happens to be masculine. That does not mean a morning is somehow male in any real-world sense. It is just a grammatical category.

But it affects other words in the sentence, especially:

• the form of the article
• adjective endings
• sometimes pronouns

That is why you get kaldur and not kalt.

In this sentence, yes.

The basic order is:

• Morgunninn = subject
• er = verb
• kaldur = complement/predicate adjective

So it lines up nicely with English:

• The morning is cold.

However, Icelandic word order is more flexible than English in many situations, and main clauses often follow a verb-second pattern. So the neutral order here is simple and English-like, but not every Icelandic sentence will match English word order so closely.

You would use a noun phrase instead of a full sentence:

• kaldi morgunninn = the cold morning

Compare:

• Morgunninn er kaldur. = The morning is cold.
• kaldi morgunninn = the cold morning

And for an indefinite phrase:

• kaldur morgunn = a cold morning

So the difference is:

• predicate adjective: er kaldur
• attributive adjective: kaldi morgunninn / kaldur morgunn

Only because it is the first word of the sentence.

Unlike German, Icelandic does not capitalize ordinary nouns just because they are nouns.

So:

• Morgunninn er kaldur. = capitalized because it starts the sentence
• in the middle of a sentence, it would normally be morgunninn