Learn Hardcore Swedish: Jag vill ha svagt kaffe på kvällen, annars sover jag dåligt. - I want weak coffee in the evening; otherwise I sleep poorly.

Because kaffe is neuter (an ett-word) when used as a mass noun. Adjectives in neuter singular take -t, so you get svagt. If you make it countable by mentioning a cup, you’d say en kopp svagt kaffe. You may also hear en kaffe in cafés (elliptical for en kopp kaffe), but if you want to add an adjective, people normally switch back to en kopp svagt kaffe.

Is kaffe an ett-word or an en-word? Why do people say en kaffe when ordering?

In dictionaries, kaffe is neuter: ett kaffe (as a substance). In café talk, en kaffe is common as a shorthand for en kopp kaffe (a portion). Grammatically they’re different uses:

Mass: svagt kaffe, kaffe är varmt
Portion (elliptical): en kaffe, tack; for modifiers, prefer en kopp svagt kaffe

Why do we need vill ha? Can I just say Jag vill svagt kaffe?

With a noun as the object of desire, Swedish uses vill ha (“want to have”). So you say Jag vill ha kaffe. Vill on its own normally takes a verb in the infinitive: Jag vill dricka kaffe (“I want to drink coffee”). Jag vill svagt kaffe is ungrammatical.

What’s the difference between vill ha kaffe and vill dricka kaffe?

vill ha kaffe: you want the thing (to receive/possess it).
vill dricka kaffe: you want the activity of drinking coffee. In many contexts both are fine, but the nuance differs.

Why is it på kvällen? Why not i kvällen or om kvällen?

Time-of-day expressions take på in the general sense:

på morgonen, på eftermiddagen, på kvällen, på natten. i kväll means “this evening” (specific, deictic). om kvällen exists but sounds old-fashioned or literary; everyday Swedish prefers på kvällen.

What’s the difference between på kvällen and på kvällarna?

på kvällen: “in the evening” as a general time period (can be generic or context-specific to a particular day).
på kvällarna: “in the evenings” (explicitly habitual/repeated). Both can work for habits; på kvällarna makes the habitual meaning clearer.

Can I move på kvällen to the front of the sentence?

Yes. Swedish main clauses are V2 (the finite verb is in second position), so:

På kvällen vill jag ha svagt kaffe, annars sover jag dåligt. Here, vill remains second after the fronted time phrase.

Why does the second clause start Annars sover jag… and not Annars jag sover…?

V2 again. When a linking adverb like annars starts the clause, the finite verb must be second:

Annars sover jag dåligt. Starting with jag would be fine too: Jag sover annars dåligt, but the nuance shifts slightly and the default here is the fronted annars.

Is the comma before annars required?

It’s optional but common. You’re linking two independent main clauses, and a comma often improves readability:

With comma (common): …, annars …
Without comma (permissible in modern minimalist punctuation): … annars …

Does annars mean “otherwise” or “or else”? Any alternatives?

Annars covers both “otherwise” and “or else,” depending on tone. Alternatives:

More explicit condition: Om jag dricker starkt kaffe på kvällen, sover jag dåligt.
Slightly informal: …, eller så sover jag dåligt.
Formal: i annat fall (rare in speech).

Why dåligt and not dålig?

dåligt functions adverbially here, modifying the verb sover (“sleep badly”). dålig is an adjective for nouns (en dålig idé). You can also say sova illa; both sova dåligt and sova illa are idiomatic, with dåligt very common in speech.

Could I say Jag sover inte bra instead of Jag sover dåligt?

Yes. inte bra is a bit milder/softer, while dåligt can sound stronger:

Jag sover inte bra ≈ “I don’t sleep well.”
Jag sover dåligt ≈ “I sleep badly/poorly.”

Does the present tense here express a general habit?

Yes. Swedish present often covers habitual or general truths: Jag vill ha … annars sover jag … If you mean specifically “this evening,” you’d mark it: i kväll vill jag ha … The present still works with time adverbials for near future.

Where would inte go if I wanted to negate the sentence?

Sentence adverbs like inte go after the finite verb:

Jag vill inte ha svagt kaffe på kvällen, annars sover jag dåligt. If you front something: På kvällen vill jag inte ha svagt kaffe. In the second clause: Annars sover jag inte bra.

Is there any nuance to svagt here? Could I say milt or lätt?

svagt kaffe means weakly brewed coffee (low strength). Alternatives:

blaskigt kaffe: watery (colloquial, negative).
milt is about flavor gentleness, less standard for coffee strength.
lättrostat/ljusrostat refers to roast level, not brew strength.

Would skulle vilja ha be more polite than vill ha?

Yes, for requests it’s more polite/softened:

Jag skulle vilja ha en kopp svagt kaffe (when ordering). In a statement of habit or preference (as in your sentence), vill ha is the normal choice.