Learn Hardcore Icelandic: Ég drekk vatn, því að kaffið er kalt. - I drink water because the coffee is cold.

It means because and introduces the reason clause: … because the coffee is cold. It’s a two-word conjunction (actually three with að) that links a cause to its result.

How is því að different from því on its own?

því að = because (introduces a reason clause).
því = therefore/so (an adverb starting a new clause).
Example: Kaffið er kalt. Því drekk ég vatn. = “The coffee is cold. Therefore I drink water.”

Can I use af því að or vegna þess að instead of því að?

Yes, with nuance:

af því að = because; very common in speech. Your sentence works with it.
því að = because; common in writing and perfectly fine in speech.
vegna þess að = because/due to the fact that; a bit more formal.
Also note the prepositional option without a full clause: vegna
- noun, e.g. Ég drekk vatn vegna kuldans (á kaffinu).

Why is there a comma before því að?

Icelandic commonly places a comma before a causal subordinate clause introduced by því að. In English we usually don’t put a comma before “because,” but in Icelandic it’s standard to set off such clauses with a comma.

What’s the word order in the því að clause?

Subordinate clauses keep normal subject–verb order: kaffið er kalt (Subject–Verb–Complement). No inversion happens inside the því að clause.

What happens to word order if I put the reason first?

If you front the subordinate clause, the following main clause uses verb-second order:

Því að kaffið er kalt, drekk ég vatn.
Note the inversion drekk ég (not ég drekk) in the main clause after the comma.

What form is drekk, and how does drekka conjugate?

drekk is 1st person singular present of að drekka “to drink.”
Present:

ég drekk
þú drekkur
hann/hún/það drekkur
við drekkum
þið drekkið
þeir/þær/þau drekka
Preterite: ég drakk, við drukkum …
Perfect: Ég hef drukkið (I have drunk).

Why is there no word for “a” before vatn?

Icelandic has no indefinite article. Mass nouns like vatn (water) are used bare for an unspecified amount. If you mean specific water, you use the suffixed definite article: vatnið = “the water.”

What case is vatn in, and why?

vatn is the direct object of drekk, so it’s in the accusative. For neuter nouns like vatn, nominative and accusative look the same in the singular, so the form doesn’t change.

Why is it kaffið and not just kaffi?

kaffið is the definite form (“the coffee”), referring to a particular coffee in context. kaffi is the indefinite/mass form (“coffee” in general). Here the speaker likely means the specific coffee they were going to drink.

Why is the adjective kalt (not kaldur)?

Adjectives agree with the noun they describe. Kaffið is neuter singular, so the predicate adjective is neuter singular: kalt.

masculine: kaldur (e.g., bíllinn er kaldur)
feminine: köld (e.g., súpan er köld)
neuter: kalt (e.g., kaffið er kalt)

Could I drop að and say því kaffið er kalt?

No. The standard conjunction is því að “because.” því alone does not mean “because” in modern usage; it means “therefore.” Keep að.

How do I pronounce the tricky letters here (þ, ð, and the words)?

Approximate guide:

þ as in English “th” in “thin” [θ]; ð as in “th” in “this” [ð].
Ég ≈ “yeh” with a soft g at the end [jɛːɣ].
drekk ≈ “drekh” (the kk is preaspirated, sounding like h+k).
vatn ≈ “vahtn” (a little h-sound before t; final n is crisp).
því ≈ “thvee.”
að ≈ “ath” (voiced “th”).
kaffið ≈ “kaf-fith.”
er ≈ “ehr.”
kalt ≈ “kalt” (k is strongly aspirated).

Does Icelandic have a separate “-ing” tense? Can I say “I am drinking water”?

There’s no dedicated progressive tense. You can express ongoing action with vera að + infinitive:

Ég er að drekka vatn, því að kaffið er kalt.
Simple present Ég drekk vatn often covers both “I drink” and “I am drinking,” depending on context.

Is ég always capitalized like English “I”?

No. ég is only capitalized at the beginning of a sentence or where normal capitalization rules apply. Unlike English “I,” it is lowercase in the middle of a sentence: Hún segir að ég drekk vatn.