Learn Hardcore Norwegian: Jeg liker å lese avisen på nettbrettet fordi skjermen er større enn på telefonen. - I like to read the newspaper on the tablet because the screen is bigger than on the phone.

Both Jeg liker å lese avisen and Jeg liker å lese avisa are correct Bokmål.
Choice depends on style, region, and personal preference. School / formal texts often prefer avisen.

Why is it “på nettbrettet” and not something like “i nettbrettet” or “med nettbrettet”?

In Norwegian, på is the normal preposition for using screens and devices in this way:

på nettbrettet = on the tablet
på telefonen = on the phone
på PC-en / på datamaskinen = on the computer
på TV-en = on the TV

You’re thinking of the content displayed on the screen, not something physically inside the device.
So you say:

Jeg liker å lese avisen på nettbrettet.
= I like to read the newspaper on the tablet.

Using i nettbrettet would sound like something is literally inside the device, which is wrong here.
med nettbrettet (with the tablet) is possible but has a different emphasis (the tablet as a tool you’re using, not the place where the newspaper is shown).

Why does “nettbrettet” have double t before the ending, and what’s its basic form?

The basic (indefinite) form is:

et nettbrett = a tablet (literally “net-board”)

This noun is neuter (intetkjønn). Neuter nouns in the definite singular end in -et, and if the word already ends in -t, you get a double t:

et nettbrett → nettbrette
- t (definite ending)
  → nettbrettet = the tablet

Other similar examples:

et hus → huset (the house)
et teppe → teppet (the blanket)
et brett → brettet (the board / tray)

So:
et nettbrett (a tablet) → nettbrettet (the tablet).

Why is it “Jeg liker å lese avisen på nettbrettet” and not “Jeg liker å lese på nettbrettet avisen”?

In Norwegian, the prepositional phrase “på nettbrettet” belongs to the verb phrase (how/where you read), not inside the noun phrase “avisen”.

[lese avisen] [på nettbrettet]
read the newspaper on the tablet

Putting it as “på nettbrettet avisen” makes it sound like “the tablet-newspaper” as one long noun phrase, which is unnatural.

So the natural order is:

Jeg liker å lese avisen på nettbrettet.
(I like to read the newspaper on the tablet.)

What does “fordi” do to the word order in “fordi skjermen er større enn på telefonen”?

fordi means “because” and introduces a subordinate clause.

In Norwegian subordinate clauses, the normal pattern is:

subject – verb – other elements

So:

skjermen (subject)
er (verb)
større enn på telefonen (rest)

→ fordi skjermen er større enn på telefonen.

Compare with main clauses, where verb usually comes second:

Skjermen er større. (The screen is bigger.)
Derfor er skjermen større. (Therefore the screen is bigger.)
But after fordi, you keep subject before verb:
… fordi skjermen er større.

Can I say “fordi at skjermen er større …”, or is “at” wrong here?

Many native speakers do say “fordi at …” in everyday speech, and you’ll hear it quite often.
However, in standard written Norwegian, especially in more formal contexts, you normally use just:

fordi skjermen er større …

So:

✅ Jeg liker å lese avisen på nettbrettet fordi skjermen er større enn på telefonen.
🟡 … fordi at skjermen er større … – common in speech, less preferred in formal writing.

Why is it “enn på telefonen” and not just “enn telefonen”?

This is about what exactly is being compared.

skjermen er større enn telefonen
= the screen is bigger than the phone (physically larger object vs object)

But here the intended comparison is:

the screen (on the tablet) vs the screen (on the phone).

Norwegian often leaves out the repeated noun and repeats only the preposition:

Full idea: skjermen på nettbrettet er større enn skjermen på telefonen.
Shortened: skjermen er større enn på telefonen.

So “enn på telefonen” is shorthand for “enn skjermen (er) på telefonen”.

Why is it “på telefonen” and not something like “i telefonen”?

As with “på nettbrettet”, Norwegian uses på for content on screens/devices:

på telefonen = on the phone (meaning on the phone’s screen)
på mobilen = on the mobile (colloquial for smartphone)

i telefonen would mean inside the phone, which is wrong for “reading on the phone.”
So:

Jeg liker å lese avisen på telefonen. = I like to read the newspaper on the phone.
Jeg hørte en lyd i telefonen. = I heard a sound in the phone (e.g. during a call).

How is the comparative “større” formed, and why not “mer stor”?

stor = big
The comparative is større = bigger.

Most common adjectives form the comparative with -ere (often with a vowel change):

stor → større (big → bigger)
lang → lengre (long → longer)
billig → billigere (cheap → cheaper)

Using mer stor (more big) is grammatically possible but sounds unnatural; you almost always use større.

So:

✅ Skjermen er større enn på telefonen.
❌ Skjermen er mer stor enn på telefonen. (very odd)

Why doesn’t Norwegian use a separate word for “the” in “avisen” and “nettbrettet”?

Norwegian (like Swedish and Danish) usually puts the definite article at the end of the noun as a suffix:

en avis – avisen (a newspaper – the newspaper)
et nettbrett – nettbrettet (a tablet – the tablet)
en skjerm – skjermen (a screen – the screen)
en telefon – telefonen (a phone – the phone)

So instead of “the newspaper”, you say “newspaper-the” (avisen).
That’s why the sentence has:

avisen, nettbrettet, skjermen, telefonen
– all in the definite form.

Is there any difference in meaning between
“Jeg liker å lese avisen på nettbrettet” and
“Jeg liker å lese avisen på telefonen”?

Grammatically, both are the same structure:

på nettbrettet = on the tablet
på telefonen = on the phone

The only difference is which device you prefer to use. That’s exactly what the second clause explains:

… fordi skjermen er større enn på telefonen.
because the screen is bigger than on the phone.