Breakdown of Ég sé um mína eigin markaðssetningu.
ég
I
minn
my
sjá um
to take care of, to be in charge of
eigin
own (one's own)
Questions & Answers about Ég sé um mína eigin markaðssetningu.
Why doesn't eigin change its ending to match the accusative feminine noun here?
Because eigin is an invariable adjective. It never changes its form regardless of the gender, number, or case of the noun it modifies. However, the possessive pronoun right before it, mína, still declines normally to match the accusative feminine singular noun markaðssetningu.
Why does eigin force the pronoun to come before the noun? Usually, possessives come after the noun in Icelandic.
You are right that normally we say markaðssetninguna mína (my marketing), placing the pronoun after a definite noun. But when you add eigin (own), the word order must flip. The possessive pronoun and eigin must go in front of the noun, and the noun itself takes the indefinite form: mína eigin markaðssetningu.
What causes the phrase mína eigin markaðssetningu to be in the accusative case in this sentence?
The phrasal verb sjá um means to take care of or to manage. The preposition um in this verb phrase dictates that the following object must be in the accusative case.
How does the word markaðssetningu break down?
It is a compound of markaður (market) and setning (setting or placing). The -s- connecting them is a genitive linking letter. Because the core word setning is a feminine noun, the entire compound noun behaves as feminine, which is why it ends in -u in the accusative case.