Learn Hardcore Dutch: Mijn ochtendroutine is langer: ik douche, ontbijt rustig en lees kort het nieuws. - My morning routine is longer: I shower, have breakfast calmly, and briefly read the news.

Dutch almost always writes compound nouns as one word.
Here ochtend (morning) + routine (routine) become ochtendroutine (morning routine).

You generally do not put a space between the parts of a compound noun in Dutch:

ochtendroutine = morning routine
ochtendwandeling = morning walk
tafelkleed = tablecloth

Also, routine is a de-word, so you say de routine, and therefore mijn ochtendroutine.

What exactly does langer mean here, and why is there no dan … (than …)?

Langer is the comparative form of lang (long): langer = longer.
In full, you could say:

Mijn ochtendroutine is langer dan vroeger.
→ My morning routine is longer than it used to be.

If the comparison is clear from the context, Dutch often omits the dan … part and just says is langer. So the sentence assumes you already know what it’s being compared to (for example: than my evening routine, than before, than yours, etc.).

Why is there a colon (:) after langer instead of a comma or full stop?

The colon introduces an explanation or list of what was just mentioned.
Here it works like:

Mijn ochtendroutine is langer: ik douche, ontbijt rustig en lees kort het nieuws.
→ The part after the colon explains in detail what this longer routine consists of.

A comma would be too weak here, and a full stop would separate the explanation too strongly. The colon shows that what follows clarifies how or why the routine is longer.

Does ik douche literally mean “I shower”, and do you need a reflexive pronoun like me?

Ik douche literally means I shower or I take a shower.
In modern Dutch, you normally say:

Ik douche. = I shower / I take a shower.

Older or more formal Dutch sometimes uses a reflexive form:

Ik douche me.

But in everyday speech ik douche (without me) is standard and completely correct.

What is ontbijt here: a noun (breakfast) or a verb (to have breakfast)?

In this sentence, ontbijt is a verb, 3rd person singular / 1st person singular of ontbijten (to have breakfast).

het ontbijt = the breakfast (noun)
ik ontbijt = I have breakfast (verb)

So ik douche, ontbijt rustig… = I shower, (I) have breakfast calmly…
The subject ik applies to all the verbs in the list: douche, ontbijt, lees.

Why is it ik douche, ontbijt rustig en lees kort het nieuws and not repeating ik before every verb?

Dutch often mentions the subject once and then leaves it out for the following verbs in a coordinated list, just like English can:

Dutch: Ik douche, ontbijt rustig en lees kort het nieuws.
English: I shower, (I) have breakfast calmly and (I) read the news briefly.

The single ik at the beginning is understood to be the subject of douche, ontbijt, and lees. Repeating ik is possible but sounds heavier and is usually unnecessary.

Why is it ontbijt rustig and lees kort (adverb after the verb)? Could the word order be different?

In main clauses, the finite verb usually comes in second position, and adverbs typically come right after the verb or later in the sentence:

Ik ontbijt rustig. = I have breakfast calmly.
Ik lees kort het nieuws. = I briefly read the news.

You can change the order a bit for emphasis, for example:

Ik lees het nieuws kort. (slightly more common than lees kort het nieuws)

Both Ik lees kort het nieuws and Ik lees het nieuws kort are grammatically correct; the difference is subtle and mostly about rhythm and emphasis.

What is the difference between rustig and rustige, and between kort and korte?

Rustig and kort in this sentence are adverbs, so they stay in their basic form:

Ik ontbijt rustig. = I have breakfast calmly.
Ik lees kort het nieuws. = I briefly read the news.

When used as adjectives before a noun, they usually get an -e:

een rustige ochtend = a calm/quiet morning
een korte pauze = a short break

So:

Adverb: rustig, kort (no ending)
Adjective before most nouns: rustige, korte

Why is the present tense (ik douche, ontbijt, lees) used to talk about a routine?

Dutch uses the simple present tense to describe routines and habits, just like English often does:

Ik sta om zeven uur op. = I get up at seven.
Ik douche elke ochtend. = I shower every morning.

You could also use something like Ik ben meestal langer bezig (I usually take longer), but simple present is the normal way to describe a regular morning routine.

Why is it het nieuws and not de nieuws?

The noun nieuws (news) is a het-word in Dutch:

het nieuws = the news

It’s also uncountable, like in English. You don’t normally say een nieuws (a news). Some related forms:

het goede nieuws = the good news
het slechte nieuws = the bad news

Is ik lees kort het nieuws the most natural version, or is ik lees het nieuws kort better?

Both are grammatically correct:

Ik lees kort het nieuws.
Ik lees het nieuws kort.

In everyday Dutch, Ik lees het nieuws kort sounds a bit more natural and is probably more frequent because the object (het nieuws) often comes earlier, with the adverb near the end.

However, your original sentence with lees kort het nieuws is still acceptable and understandable; it just has a slightly different rhythm.

How do you pronounce ochtendroutine, douchen, and nieuws?

Approximate pronunciations (in simple English-style hints):

ochtendroutine → OCH-tend-roo-TEE-nuh
- ch like the harsh sound in Scottish loch or German Bach
- stress on -tee-
douchen → DOO-shen
- ou like oo in food
- ch here is like sh in shower (this verb comes from French douche)
nieuws → NEEuws
- nie like nee in knee
- the uw is like quickly saying oo
  - w
- final s is like English s

These are approximations; the real sounds sit between English sounds but this should get you close.