Ég finn ekki bókina mína.

A word-for-word breakdown is:

• Ég = I
• finn = find / am finding
• ekki = not
• bókina = the book (specifically the accusative singular form of bókin)
• mína = my (agreeing with bókina)

So the structure is essentially I find not the-book my, which corresponds to natural English I can’t find my book or I do not find my book.

Finna is the infinitive, meaning to find.

In the sentence, you need the verb conjugated for I, so Icelandic uses:

• ég finn = I find

This is the 1st person singular present tense of finna.

A few forms are:

• að finna = to find
• ég finn = I find
• þú finnur = you find
• hann/hún/það finnur = he/she/it finds

So finn is used because the subject is ég.

In Icelandic, ekki usually comes after the finite verb in a simple main clause.

So:

• Ég finn ekki ... = I do not find ...

This is the normal placement.

English uses do not find, but Icelandic does not need a separate helper verb like do here. It simply puts ekki after the conjugated verb.

Compare:

• Ég sé ekki hann. = I do not see him.
• Ég skil ekki þetta. = I do not understand this.

Because bókina is the form needed for a definite direct object.

Here is the pattern:

• bók = book (indefinite, basic dictionary form)
• bókin = the book (nominative singular)
• bókina = the book (accusative singular)

The verb finna takes a direct object in the accusative, so book must appear in the accusative form.

Since the sentence means my book as a specific book, the noun is definite, so Icelandic uses the definite form:

• Ég finn bók. = I find a book.
• Ég finn bókina. = I find the book.

In your sentence, it is bókina because it is:

1. singular
2. feminine
3. definite
4. accusative

Because Icelandic possessives must agree with the noun they describe in gender, number, and case.

The noun here is bókina, which is:

• feminine
• singular
• accusative

So the possessive must match that form:

• mín = not the right form here
• mína = the correct feminine singular accusative form

You can compare:

• bókin mín = my book (nominative)
• bókina mína = my book (accusative)

So the ending changes because the grammatical role changes.

This is very normal in Icelandic.

English says simply my book, without the. Icelandic often uses the definite noun + possessive pattern:

• bókin mín = my book
• bókina mína = my book (accusative)

So even though English does not say the my book, Icelandic commonly does the equivalent structurally.

There is also a pattern with the possessive before the noun:

• mín bók

But that is often more emphatic, literary, or contrastive, depending on context. For an ordinary neutral sentence, bókin mín / bókina mína is very common.

In normal English, the most natural translation is often:

• I can’t find my book.

But the Icelandic sentence itself is literally closer to:

• I do not find my book.

In practice, Icelandic often uses this kind of present-tense negative sentence where English prefers can’t find.

So if a learner sees Ég finn ekki bókina mína, they should usually understand it as the natural everyday idea:

• I can’t find my book.

The verb finna takes a direct object in the accusative.

That is why:

• bók becomes bókina in this sentence
• not bókin

This is something Icelandic learners often have to memorize with verbs: many verbs regularly take the accusative object.

So with finna:

• að finna eitthvað = to find something

Examples:

• Ég finn lykilinn. = I find the key.
• Ég finn ekki símann minn. = I can’t find my phone.

The noun after finna is what is being found, so it appears as the direct object, usually in the accusative.

Icelandic word order is somewhat flexible, but not everything sounds equally natural.

The most neutral order here is:

• Ég finn ekki bókina mína.

That is what you should learn first.

A few notes:

• ekki normally stays after the finite verb in a simple statement.
• mína normally stays with bókina.
• Moving things around can create emphasis, contrast, or a more marked style.

For example, changing the order too freely may sound unnatural to learners’ ears until they have more experience with Icelandic syntax.

So the safest answer is: yes, Icelandic has some flexibility, but Ég finn ekki bókina mína is the standard neutral version.

Because Icelandic usually puts the definite article onto the end of the noun instead of using a separate word like English the.

So:

• bók = book
• bókin = the book
• bókina = the book in the accusative

That -in / -na type ending is the definite article attached to the noun.

This is a very important feature of Icelandic grammar. Instead of saying a separate word before the noun, Icelandic often builds definiteness directly into the noun form.

Then both the noun and the possessive would change to match plural accusative feminine.

For example:

• Ég finn ekki bækurnar mínar. = I can’t find my books.

Compare the singular and plural:

• bókina mína = my book
• bækurnar mínar = my books

Notice that both parts change:

• bókina → bækurnar
• mína → mínar

That happens because Icelandic marks number, gender, and case quite consistently.

A rough learner-friendly pronunciation is:

• yeg finn ehk-ki BOH-ki-na MEE-na

A few helpful notes:

• Ég sounds roughly like yeg
• finn has a short i, like fin in English, but with a doubled consonant feel
• ekki is roughly ehk-ki
• bókina has stress on the first syllable: BOH-ki-na
• mína has a long í, like mee-na

As in most Icelandic words, the main stress is on the first syllable of each word.