Learn Hardcore Swedish: De öppnar fönstret så att rummet blir tystare. - They open the window so that the room becomes quieter.

It most naturally signals a result: They open the window, and as a result the room becomes quieter. If you want to make purpose explicit, use för att:

De öppnar fönstret för att rummet ska bli tystare.
De öppnar fönstret för att göra rummet tystare.

Do I need a comma before så att?

Generally no. Swedish normally doesn’t use a comma between a main clause and a following så att-clause: De öppnar fönstret så att … You might add a comma for a long or complex first clause, but it’s not required here.

Why is it blir tystare and not är tystare?

Blir (becomes) describes a change of state caused by the action. Är (is) would state a static fact. After an action like opening a window, Swedish prefers bli to show the resulting change: … så att rummet blir tystare.

Is tystare the correct comparative, or can I say mer tyst?

Use tystare. One-syllable adjectives typically take the -are comparative: tyst → tystare → tystast. Mer tyst sounds odd in standard Swedish.

Why are fönstret and rummet in the definite form?

They refer to specific, known things: the window and the room in question. Both are neuter nouns:

ett fönster → fönstret (the window)
ett rum → rummet (the room)

Could I say De öppnar ett fönster … instead?

Yes, if you mean any window (not a specific one). De öppnar ett fönster = they open some window. De öppnar fönstret = they open the particular window you and the listener have in mind.

What’s the word order after så att?

Keep normal subordinate-clause order: Subject before verb. Hence … så att rummet blir tystare (not … så att blir rummet tystare). If you add negation, it goes after the subject: … så att rummet inte blir tystare.

Can I write dom here, and how do I pronounce de?

In standard writing, use de for subject and dem for object. Many Swedes pronounce both as dom. Writing dom is common informally and in some media, but in formal contexts stick to de/dem. Here it’s subject, so De öppnar …

Why present tense (öppnar, blir) for something that hasn’t happened yet?

Swedish often uses present tense for immediate or general future/result: De öppnar fönstret så att … You could say kommer att bli for a future emphasis, but blir is the natural choice here.

How do I say the same idea with för att?

Two common options:

De öppnar fönstret för att rummet ska bli tystare. (purpose + finite clause with ska)
De öppnar fönstret för att göra rummet tystare. (purpose + infinitive)

What changes if I use only så instead of så att?

Then så works like a coordinating linker meaning then/so, and you invert the following clause:

De öppnar fönstret, så blir rummet tystare. With så att, no inversion: … så att rummet blir tystare.

Where does inte go?

To negate the result: De öppnar fönstret så att rummet inte blir tystare.
To negate the action: De öppnar inte fönstret så att rummet blir tystare. The first says the room does not become quieter; the second says they don’t open the window for that result (scope difference).

Is öppna upp okay?

You’ll hear öppna upp, but many consider it redundant. In careful writing, plain öppna is preferred. So De öppnar fönstret … is best.

Pronunciation tips for tricky vowels here (ö, u, y)?

ö in öppnar: rounded front vowel (like German ö). Keep lips rounded: roughly [œ/ø].
u in rummet: central rounded vowel [ʉ]/[ɵ], not like English “oo.”
y in tystare: front rounded vowel [ʏ] (like French u in lune). Say English “ee” while rounding your lips.

Can I front the så att clause?

It’s uncommon and sounds heavy: Så att rummet blir tystare öppnar de fönstret is marked. Keep the så att clause after the main clause.

Any irregular forms to watch for in these words?

bli: blir (pres) – blev (past) – blivit (supine) [irregular].
öppna: öppnar – öppnade – öppnat [regular].
Noun patterns:
- ett rum → rummet; plural rum, definite plural rummen.
- ett fönster → fönstret; plural fönster, definite plural fönstren.