Learn Hardcore Swedish: Hon märker ingen skillnad när hon dricker svagt kaffe. - She notices no difference when she drinks weak coffee.

skillnad is a common gender noun (an en-word: en skillnad).
Therefore you use ingen (common gender, singular):
- ingen skillnad = no difference

If it were a neuter noun (an ett-word), you would use inget:

inget problem (problem = ett problem)

And for plurals, you use inga:

inga skillnader = no differences

Why is it ingen skillnad and not ingen skillnaden?

Swedish normally uses the indefinite form of the noun after ingen/inget/inga:

ingen skillnad — correct
ingen skillnaden — incorrect

You’d only use the definite form (skillnaden) with a definite article or determiner like:

den här skillnaden = this difference
skillnaden = the difference

With ingen, the pattern is:
ingen + [indefinite noun] → ingen skillnad

What exactly does märker mean, and how is it different from lägger märke till?

märker is the present tense of märka, which means roughly to notice.

Hon märker ingen skillnad = She doesn’t notice any difference.

lägger märke till also means to notice, but it’s a bit more explicit/emphatic and slightly more formal or “complete”:

Hon lägger inte märke till någon skillnad.

Differences in use:

märker is shorter and very common in everyday speech.
lägger märke till can sound a bit more deliberate, like take notice of.

In this sentence, märker ingen skillnad is the most natural everyday choice.

Why is it svagt kaffe and not svag kaffe?

Adjectives in Swedish agree with the gender and number of the noun:

The base form of the adjective is svag (weak).
kaffe is a neuter noun (an ett-word: ett kaffe, grammatically speaking).
With neuter singular nouns in the indefinite form, adjectives end in -t:
- svagt kaffe = weak coffee

Compare:

en svag sås (sauce, common gender)
ett svagt kaffe (coffee, neuter) → in the sentence this becomes svagt kaffe (no article, but still neuter, so svagt).

Is svagt kaffe the normal way to say “weak coffee”? Are there other options?

Yes, svagt kaffe is the standard, neutral way to say weak coffee.

You might also hear:

blaskigt kaffe – watery, thin coffee (colloquial, slightly negative)
utspätt kaffe – diluted coffee
milt kaffe – mild coffee (focusing more on taste/strength in terms of roast)

But in a neutral sentence like this, svagt kaffe is the most typical expression.

What tense are märker and dricker, and what are their infinitives?

Both verbs are in the present tense.

märker ← infinitive: märka
- jag märker (I notice)
- hon märker (she notices)
dricker ← infinitive: dricka
- jag dricker (I drink)
- hon dricker (she drinks)

In Swedish, present tense is used both for:

actions happening now: “She is drinking”
and habitual actions: “She drinks (regularly)”

So the same present form covers English drinks and is drinking, depending on context.

Why is it när hon dricker svagt kaffe and not om hon dricker svagt kaffe?

Both när and om can sometimes be translated as when, but they differ:

när = when, for time, especially repeated or general situations:
- Hon märker ingen skillnad när hon dricker svagt kaffe.
  → Whenever she drinks weak coffee (in general), she doesn’t notice any difference.
om = if/when, for conditions or hypothetical situations:
- Hon märker ingen skillnad om hon dricker svagt kaffe.
  → If she drinks weak coffee, she doesn’t notice any difference. (more conditional, “in that case”)

In your sentence, när makes it sound like a regular, repeated situation, which is natural here.

Could I change the word order to Hon dricker svagt kaffe när hon märker ingen skillnad?

That word order is grammatically possible, but the meaning and focus change and it becomes a bit odd.

Original:

Hon märker ingen skillnad när hon dricker svagt kaffe.
→ The main information is about not noticing a difference; the time frame is when she drinks weak coffee.

Your version:

Hon dricker svagt kaffe när hon märker ingen skillnad.
→ Now the main information is she drinks weak coffee, and the condition/time is when she doesn’t notice any difference.

It sounds strange because not noticing a difference is a result of drinking weak coffee, not usually the trigger for starting to drink it. So the original word order is the natural one for this idea.

Why can’t I say Hon märker skillnad inte instead of Hon märker ingen skillnad?

Two points:

Placement of “inte”
In Swedish, inte usually comes after the verb but before the object in a main clause:
- Hon märker inte någon skillnad. (correct)
- Hon märker skillnad inte. (sounds foreign/incorrect in normal speech)
Choice of negation
In your sentence, Swedish normally prefers using ingen/inget/inga before the noun:
- Hon märker ingen skillnad. (very natural)
- Hon märker inte någon skillnad. (also correct, slightly more explicit)
- Hon märker skillnad inte. (wrong word order and wrong pattern)

So the two good options are:

Hon märker ingen skillnad.
Hon märker inte någon skillnad.

Can I drop the second hon and say Hon märker ingen skillnad när dricker svagt kaffe?

No. In Swedish, you generally must have a subject in each clause, including subordinate clauses.

So you need:

… när hon dricker svagt kaffe.

Dropping the subject like in some languages (or like informal English when Ø drinks coffee) is not allowed in standard Swedish:

när dricker svagt kaffe → ungrammatical

Why isn’t there any article before svagt kaffe? Why not ett svagt kaffe?

Kaffe is often treated as a mass noun (like “water”, “milk”):

In English we say: “She drinks coffee”, not “She drinks a coffee” (unless we mean a cup).
Similarly in Swedish: Hon dricker svagt kaffe. = She drinks weak coffee (in general, as a substance).

You might use an article in contexts like:

ett kaffe = a coffee (one serving, one cup, especially in cafés)
ett svagt kaffe, tack = a weak coffee, please

But in your sentence, we are talking about coffee in general, so no article: svagt kaffe.

Can hon refer to things, or only to people?

In modern standard Swedish:

hon = she (normally for female persons)
han = he (normally for male persons)
den / det = it (for things, animals, and also sometimes people when gender is irrelevant)
hen = gender-neutral pronoun for persons (increasingly common)

In this sentence, hon clearly refers to a female person.
You wouldn’t normally use hon for a thing like a machine; you’d use den or det instead:

Den märker ingen skillnad… / Det märker ingen skillnad… (depending on the noun’s gender)

Are there more colloquial or alternative ways to say märker ingen skillnad?

Yes, several alternatives exist, with slightly different tones:

Hon märker ingen skillnad. – neutral, standard.
Hon känner ingen skillnad. – literally “feels no difference”; more about physical/subjective feeling.
Hon märker inget. – “She doesn’t notice anything.” (more general)
Hon märker ingen större skillnad. – “She doesn’t notice any big difference.” (softens it a bit)

But for the straightforward idea, Hon märker ingen skillnad is the most common and natural.