Kennarinn segir að bandstrikið sé ekki rétt.

In Icelandic, the definite article is usually attached to the end of the noun instead of standing as a separate word.

• kennari = teacher

• kennarinn = the teacher

• bandstrik = hyphen
• bandstrikið = the hyphen

The exact ending changes depending on the noun’s gender, number, and case. So -inn and -ið are both forms of the, not random endings.

Segir is the 3rd person singular present tense of the verb segja, meaning to say.

So:

• ég segi = I say
• þú segir = you say
• hann/hún/það segir = he/she/it says

Here, Kennarinn segir means The teacher says.

Not necessarily. Kennari is a grammatically masculine noun, but grammatical gender and real-life gender are not always the same thing.

So kennarinn is the normal definite form of kennari, and by itself it does not automatically tell you whether the teacher is a man or a woman. Context would decide that.

There are two reasons:

1. The base noun is bandstrik, which is itself a single noun.
2. The definite article is attached to it: bandstrik + ið = bandstrikið.

Icelandic also writes compound nouns as one word much more often than English does. So long words like this are very normal.

Here að means that.

It introduces the clause after segir:

• Kennarinn segir að ... = The teacher says that ...

This is a different use from the að used before an infinitive, where it can mean to:

• að lesa = to read

So Icelandic að has more than one job. In this sentence, it is a conjunction meaning that.

Because sé is the subjunctive form of vera (to be).

• er = indicative present, is
• sé = subjunctive present, also is in English

In standard Icelandic, after verbs like segja when reporting what someone says, thinks, or claims, the subordinate clause often uses the subjunctive. It helps show that this is reported content rather than a plain direct statement by the speaker.

So:

• Kennarinn segir að bandstrikið sé ekki rétt
  = The teacher says that the hyphen is not correct.

An English speaker usually does not see any difference in translation, because English often just uses is either way.

Because it agrees with bandstrikið, which is neuter singular.

In Icelandic, adjectives often change form to match the noun they describe or the subject they refer to. Here rétt means correct/right, and it is in the form that matches a neuter singular subject.

So the idea is:

• bandstrikið = a neuter singular noun
• therefore rétt must match it

That is why you do not see a masculine-looking form such as réttur here.

Both are nominative singular.

• Kennarinn is the subject of the main clause.
• bandstrikið is the subject of the subordinate clause after að.

So structurally, the sentence is:

• Kennarinn = subject
• segir = verb
• að bandstrikið sé ekki rétt = content clause

And inside that content clause:

• bandstrikið = subject
• sé = verb
• ekki rétt = not correct

Because this is a subordinate clause introduced by að.

In main clauses, Icelandic often follows a verb-second pattern. But after a subordinating word like að, the word order is usually more like:

• að + subject + finite verb + ekki + complement

So:

• að bandstrikið sé ekki rétt

This is normal Icelandic subordinate-clause order.

Because ekki usually comes after the finite verb in a neutral clause.

So Icelandic often has:

• er ekki
• sé ekki
• kemur ekki

That is why you get:

• bandstrikið sé ekki rétt

This is the ordinary, unmarked placement. Moving ekki elsewhere can create emphasis or a different structure, but this sentence uses the standard pattern.

Usually bandstrik means hyphen. In some contexts, learners may see punctuation words translated a bit loosely, but here hyphen is almost certainly the intended meaning.

So bandstrikið is best understood here as the hyphen.