Kennarinn gefur stutta leiðréttingu þegar stafsetningin mín er röng.

Icelandic usually puts the definite article the at the end of the noun.

• kennari = teacher
• kennarinn = the teacher
• stafsetning = spelling
• stafsetningin = the spelling

The endings are different because the article changes with gender, number, and case.

• -inn here is the masculine nominative singular ending in kennarinn
• -in here is the feminine nominative singular ending in stafsetningin

So the article is not one fixed form.

Because Icelandic has no indefinite article. There is no separate word that exactly equals English a/an.

So:

• stutt leiðrétting / stutta leiðréttingu = a short correction / short correction, depending on the grammar of the sentence

The noun simply appears without a definite article if it is indefinite.

Because they are the direct object of gefur, and that makes them accusative.

• leiðrétting is the basic noun
• leiðréttingu is its accusative singular form
• stuttur is the adjective
• stutta is the feminine accusative singular form that matches leiðréttingu

In Icelandic, adjectives must agree with the noun they describe in:

• gender
• number
• case

So stutta leiðréttingu is a matching pair.

It is accusative singular.

The verb gefa often works like give in English:

• subject = the giver
• direct object = the thing being given
• often also an indirect object = the person receiving it

In this sentence, stutta leiðréttingu is the thing being given, so it is in the accusative.

A recipient can be added, but it does not have to be stated.

For example:

• Kennarinn gefur mér stutta leiðréttingu. = The teacher gives me a short correction.

Here, the sentence leaves the recipient unstated because it is either obvious from context or not important. That is completely normal.

Both can mean my spelling, but stafsetningin mín is a very common and neutral Icelandic pattern.

Icelandic often says:

• noun + definite article + possessive
• literally something like the spelling mine

So:

• stafsetningin mín = my spelling

You can also say mín stafsetning, but that often sounds more emphatic, contrastive, or stylistically different.

Because in Icelandic, a postposed possessive often goes together with a definite noun.

So this is normal Icelandic:

• stafsetningin mín
• bókin mín = my book
• húsið mitt = my house

To an English speaker this can feel like the my spelling, but that is not how Icelandic speakers hear it. It is just a standard possessive structure.

Because mín has to agree with stafsetningin.

stafsetning is:

• feminine
• singular
• here nominative

So the possessive also takes the feminine singular nominative form:

• masculine: minn
• feminine: mín
• neuter: mitt

That is why the sentence uses mín.

Because röng is the form that agrees with stafsetningin mín.

The adjective rangur means wrong and changes form by gender:

• masculine: rangur
• feminine: röng
• neuter: rangt

Since stafsetning is feminine singular, Icelandic uses:

• stafsetningin mín er röng

This is also a good example of a predicate adjective: after er (is), the adjective still agrees with the subject.

Because þegar introduces a subordinate clause, and subordinate clauses do not use main-clause verb-second word order in the same way.

So after þegar, the normal order is:

• stafsetningin mín er röng
• subject + verb + complement

That is why the sentence says:

• þegar stafsetningin mín er röng

not

• þegar er stafsetningin mín röng

In a sentence like this, þegar can often feel like when or whenever, depending on context.

Because the sentence sounds like a general or repeated situation, English might naturally translate it as:

• when my spelling is wrong
• or whenever my spelling is wrong

So þegar is not limited to only one single event here.

Yes. Many feminine nouns ending in -ing follow a similar pattern.

For example, nouns of this type often have:

• nominative singular: -ing
• accusative singular: -ingu

So:

• leiðrétting → leiðréttingu

That pattern is useful to recognize, because you will see it in many Icelandic feminine nouns.