Dóttir mín er góður leikmaður og talar alltaf við liðsfélagana sína.

Both are possible, but dóttir mín is the more neutral, everyday way to say my daughter in Icelandic.

A possessive like mín often comes after the noun in ordinary statements:

• dóttir mín = my daughter
• bíllinn minn = my car

Putting the possessive first, as in mín dóttir, usually adds emphasis, contrast, or a slightly more emotional/literary tone:

• mín dóttir can feel more like my daughter (as opposed to someone else’s daughter)

So here dóttir mín is simply the normal, unmarked wording.

Because possessive pronouns in Icelandic must agree with the noun they belong to in gender, number, and case.

Here the noun is dóttir, which is:

• feminine
• singular
• nominative

So the correct form is mín.

Compare the nominative singular forms:

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

So:

• sonur minn = my son
• dóttir mín = my daughter
• barn mitt = my child

Because góður agrees with leikmaður, not with the real-life sex of the person being described.

The noun leikmaður is grammatically masculine, so the adjective must also be masculine:

• góður leikmaður

This is a very important Icelandic point: grammatical gender and natural gender are not always the same thing.

So even if the person is a girl or woman, you can still say:

• Hún er góður leikmaður.

That does not mean she is male. It only means the noun leikmaður is masculine as a word.

Yes. After vera (to be), a predicate noun is usually in the nominative in Icelandic.

So in:

• Dóttir mín er góður leikmaður

both dóttir mín and góður leikmaður are nominative.

That is why you get:

• leikmaður = nominative singular
• góður = nominative singular masculine, agreeing with leikmaður

Talar is the 3rd person singular present tense of tala (to speak / to talk).

The subject is dóttir mín, which is third person singular, so the verb must also be third person singular:

• ég tala = I speak
• þú talar = you speak
• hún talar = she speaks

So:

• Dóttir mín talar ... = My daughter speaks/talks ...

That is a very common and natural position for adverbs like alltaf (always) in Icelandic.

Here the structure is:

• subject + verb + adverb + prepositional phrase

So:

• Dóttir mín ... talar alltaf við ...

This is a normal neutral word order. Icelandic word order can move around for emphasis, but talar alltaf is very standard.

With tala, Icelandic commonly uses the expression tala við einhvern, which means to talk to someone or to talk with someone.

So:

• tala við liðsfélagana sína = talk to/with her teammates

Be careful: við has several meanings in Icelandic depending on context, but after tala it is the normal preposition for the person you are speaking to.

Liðsfélagana is the definite accusative plural of liðsfélagi, which means teammate.

So the parts are roughly:

• liðsfélagi = teammate
• liðsfélagana = the teammates

It is accusative plural because við takes the accusative in this expression:

• tala við einhvern

And it is definite because Icelandic usually adds the as a suffix to the noun rather than using a separate word:

• liðsfélagar = teammates
• liðsfélagarnir = the teammates (nominative plural)
• liðsfélagana = the teammates (accusative plural)

Because sína is a reflexive possessive, used when the possessor is the same as the subject of the clause.

Here the subject is dóttir mín, and the teammates belong to her, so Icelandic uses sinn/sín/sitt:

• Dóttir mín ... talar við liðsfélagana sína.
• literally: My daughter ... talks with teammates her-own

This means her own teammates.

If you used hennar instead, it would usually mean someone else’s female person’s teammates, or it could sound ambiguous.

Also, sína agrees with liðsfélagana in form. Since liðsfélagana is masculine accusative plural, the correct reflexive form is sína.