Ég tek lyklana upp úr vasanum áður en ég fer inn.

Tek is the 1st person singular present tense of taka.

So:

• að taka = to take
• ég tek = I take

This verb is a little irregular, because the stem vowel changes from a to e in the present tense.

Because lyklana is the definite accusative plural form of lykill.

Here is the logic:

• lykill = a key
• lyklar = keys
• lyklana = the keys

It is in the accusative because it is the direct object of tek: you are taking the keys.

A learner often expects something like lyklarnir, but lyklarnir is the nominative plural definite form, which is used for the subject, not the object.

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

So:

• lyklana = lykl-
  • -ana = the keys
• vasanum = vasa-
  • -num = the pocket

This is very normal in Icelandic. English uses a separate word, but Icelandic usually uses a suffix.

Upp is a directional particle/adverb. With taka, it often helps create the sense of pick up or take up/out.

In this sentence, tek lyklana upp úr vasanum suggests physically taking the keys up and out from the pocket.

English often just says take the keys out of my pocket, but Icelandic often likes these little directional words such as:

• upp = up
• inn = in
• út = out
• niður = down

So upp is very natural here, even if English would not always translate it separately.

Because úr means out of or from inside.

It is the right preposition when something comes from inside something else:

• úr vasanum = out of the pocket
• úr töskunni = out of the bag
• úr húsinu = out of the house

Also, úr requires the dative case, which is why vasi changes to vasanum.

Because úr governs the dative, and vasanum is the dative singular definite form of vasi.

Very roughly:

• vasi = a pocket
• vasann = the pocket (accusative)
• vasanum = the pocket (dative)

Since the sentence has úr, you need the dative form:

• úr vasanum

So the ending is there because of the preposition and the case it requires.

Literally, it means the pocket.

But in Icelandic, it is very common to leave out a possessive like my when it is obvious from the context. So úr vasanum can naturally be understood as out of my pocket here.

English usually prefers my pocket, but Icelandic often does not need to say that explicitly if the owner is clear.

If you really wanted to make it explicit, you could say something like úr vasanum mínum, but that is often unnecessary.

Inn is a directional adverb meaning in or inside when there is movement.

So:

• ég fer inn = I go in / I go inside

This is different from inni, which usually means inside as a location, not direction:

• ég er inni = I am inside

A useful contrast is:

• fara inn = to go in
• vera inni = to be inside

Because áður en ég fer inn is a full subordinate clause, and it needs its own subject.

So the sentence has:

• main clause: Ég tek lyklana upp úr vasanum
• subordinate clause: áður en ég fer inn

English can sometimes reduce this kind of structure, as in before going in, but Icelandic here uses a full clause, so ég appears again.

Áður en is a fixed expression meaning before when it introduces a clause.

So:

• áður en ég fer inn = before I go in

It is best learned as a unit. It is very common in Icelandic for linking one action to another in time.

Sometimes yes, but Ég tek lyklana upp úr vasanum is very natural and idiomatic.

With verb particles like upp, Icelandic can sometimes place the object either before or after the particle, but the exact preference depends on the verb, the object, and the whole phrase.

A few useful tendencies:

• with a full noun phrase, both orders may be possible in some contexts
• with a pronoun, the object very often comes before the particle

So something like ég tek þá upp sounds more natural than ég tek upp þá.

In your sentence, the given order is a very normal one.

Because Icelandic often uses the present tense in sentences like this for:

• habitual actions
• general statements
• near-future or sequence-like meaning

So Ég tek ... áður en ég fer inn can mean something like:

• this is what I usually do
• this is what I do at that moment
• this is the normal sequence of actions

That is very similar to English, which also often uses the present in this kind of sentence: I take the keys out of my pocket before I go in.