Learn Hardcore Dutch: De kabel zit los.

Dutch often uses “position verbs” to describe how/where something is situated. Zitten can mean “to be fixed/inserted/held in place.” With things that are supposed to be attached (screws, cables, buttons), Dutch commonly says they zitten loose or tight.

De kabel zit los suggests the cable is in its socket/holder but not securely; it wobbles or can be pulled out easily.
De kabel is los is a more general state: it’s loose/free, possibly (fully) detached. It’s fine, just less specific.

Is this actually the separable verb loszitten?

Yes. Dictionary form: loszitten (“to be loose/not firmly attached”). In main clauses the prefix separates:

Present: De kabel zit los.
Past: De kabel zat los.
Perfect: De kabel heeft losgezeten.
Subordinate clause: …dat de kabel loszit. It uses the auxiliary hebben in perfect tenses.

What does zitten mean here? It doesn’t look like “to sit.”

Here zitten means “to be positioned/held in place.” It’s part of a Dutch pattern:

zitten: inserted/held in something (screws, plugs, teeth, buttons)
staan: upright/standing (bottles, towers, printed text “staat op de pagina”)
liggen: lying/flat/on a surface (books on a table, cables on the floor)
hangen: hanging/suspended (lamps, hanging cables) So a cable that isn’t firmly connected typically “zít los.”

Is los an adjective, and why doesn’t it have an -e here?

Yes, los is an adjective used predicatively (after a verb like zijn/worden/zitten/liggen). Predicative adjectives do not take the -e ending:

Predicative: De kabel zit los.
Attributive (before a noun): een losse kabel, de losse kabel. For neuter diminutives, note the usual rule: een los kabeltje but het losse kabeltje.

What gender is kabel, and what are the plural and diminutive?

Gender: common gender (de-word) → de kabel
Plural: kabels → De kabels zitten los.
Diminutive: het kabeltje → Het kabeltje zit los.

How do I negate or soften/strengthen this sentence?

Negation: De kabel zit niet los. (“The cable isn’t loose.”)
To say it’s not properly secure: De kabel zit niet (goed) vast.
Degree:
- De kabel zit een beetje los.
- De kabel zit best wel/erg/heel/volledig/helemaal los.

How do I make a yes/no question or a wh-question with this?

Yes/no: Zit de kabel los?
Wh-:
- Waarom zit de kabel los? (Why…)
- Waar zit de kabel los? (At which point is it loose?) Remember: in yes/no questions, the finite verb comes first.

What’s the difference between zit/hangt/ligt/is los for a cable?

zit los: in place but wobbly/poorly secured (very idiomatic for connectors, screws).
hangt los: dangling (often one end is unattached).
ligt los: lying around unattached on a surface.
is los: general state “is loose/free,” often implying not attached at all. Opposite is zit vast (“is firmly attached”).

How do I say “The cable has come loose” or “was disconnected/unplugged”?

Change of state (came loose): De kabel is losgeraakt / losgekomen.
Disconnected (deliberately): De kabel is losgekoppeld.
Unplugged (power plug): De stekker zit niet in het stopcontact or De stekker is eruit.
If you did it: Ik heb de kabel losgemaakt.

What’s the conjugation of zitten I should remember?

Present: ik zit, jij/u zit, hij/zij/het zit, wij/jullie/zij zitten
Past: ik/hij zat, wij/jullie/zij zaten
Past participle: gezeten (for loszitten: losgezeten)

Is zit los used beyond cables? What other nouns commonly “zitten los”?

Yes, very common with things meant to be fixed:

De schroef zit los. (screw)
Mijn kies zit los. (tooth)
Het handvat zit los. (handle)
Het wiel zit los. (wheel) It implies they’re in place but not secured.

Any quick pronunciation tips?

de: duh
kabel: KAA-bəl (long “aa” like in “father”)
zit: zit (short i as in “bit”)
los: loss (short o)