Í janúar byrja ég að skipuleggja árið, en í febrúar er ég stundum enn að venjast nýrri rútínu.

In Icelandic, í is the normal preposition used with months to mean in:

• í janúar = in January
• í febrúar = in February

So this is a very common pattern for dates and time expressions. With month names, learners usually just memorize the full expression as a chunk.

This is because Icelandic usually follows a verb-second pattern in main clauses.

That means the finite verb normally comes in the second slot of the sentence. If you put a time phrase first, the verb comes next, and the subject follows it:

• Í janúar byrja ég ...
• Í febrúar er ég ...

Compare the more neutral order:

• Ég byrja að skipuleggja árið í janúar.
• Ég er stundum enn að venjast nýrri rútínu í febrúar.

Both are possible, but starting with Í janúar or Í febrúar puts more emphasis on the time.

After byrja, Icelandic normally uses að + infinitive:

• byrja að gera eitthvað = to start doing something

So:

• byrja að skipuleggja árið = start to plan the year

Here að works much like English to before an infinitive.

This is the Icelandic vera að + infinitive construction:

• vera að gera eitthvað = to be doing something

So:

• er ég að venjast = I am getting used to / I am in the process of getting used to

It emphasizes that the action is ongoing. In this sentence, the speaker is saying that in February, the adjustment process is sometimes still happening.

Because árið means the year, while ár means just year.

• ár = year
• árið = the year

Icelandic usually adds the definite article as an ending on the noun. Here the speaker is talking about a specific year, so árið is natural:

• skipuleggja árið = plan the year

Because venjast takes the dative case.

The noun rútína is feminine, and both the noun and the adjective have to match the dative singular form:

• nominative: ný rútína
• accusative: nýja rútínu
• dative: nýrri rútínu

So after venjast, you get:

• venjast nýrri rútínu = get used to a new routine

This is a very important pattern to learn: some Icelandic verbs require a case other than the accusative.

Venjast is a verb ending in -st, often called a middle voice form.

Its basic meaning is:

• venjast = get used to, become accustomed to

It is related to venja, but venjast should really be learned as its own verb, because its meaning and grammar are specific. One key thing to remember is that venjast normally takes the dative.

So it is best to memorize it like this:

• venjast + dative = get used to something

They do different jobs:

• stundum = sometimes
• enn = still

So:

• stundum enn að venjast means sometimes still getting used to

The sentence is not just saying that the process is still continuing; it is saying that this is only true sometimes.

Yes, to some extent.

For example, you could also say:

• Ég byrja að skipuleggja árið í janúar.
• Í janúar byrja ég að skipuleggja árið.

Both are grammatical, but they emphasize different things. Starting with Í janúar makes the time frame more prominent.

The same applies to the second clause:

• Í febrúar er ég stundum enn að venjast nýrri rútínu.
• Ég er stundum enn að venjast nýrri rútínu í febrúar.

The version in your sentence sounds very natural because it contrasts January and February clearly.

Because en means but, and it joins two main clauses:

• Í janúar byrja ég að skipuleggja árið
• en í febrúar er ég stundum enn að venjast nýrri rútínu

In normal writing, Icelandic often uses a comma before a coordinating conjunction like en when it connects full clauses. It helps show the pause and the contrast between the two parts.