Learn Hardcore German: Der Lärm im Treppenhaus nervt mich. - The noise in the stairwell annoys me.

Lärm = unpleasant, often continuous noise (traffic noise, construction noise, loud neighbors).
Geräusch = sound or noise in a neutral way; it can be good, bad, or neutral (the sound of the wind, a strange noise in the kitchen).
Krach = loud, often sudden noise; can also mean a loud quarrel. It sounds more colloquial and stronger than Lärm.

So Der Lärm im Treppenhaus nervt mich implies the noise is definitely annoying, not just any sound.

Why is it der Lärm and not die or das Lärm?

In German, every noun has a grammatical gender that you normally just have to learn:

der Lärm (masculine)
die would be feminine
das would be neuter

Lärm happens to be masculine, so in the nominative singular it always takes der.

In this sentence, Der Lärm is the subject (the thing doing the action — annoying), so it appears in nominative: der Lärm.

What case is der Lärm in here, and why?

Der Lärm is in the nominative case.

Reason: It’s the subject of the sentence — the thing that performs the action of the verb nervt (annoys).

Basic pattern:

Wer oder was nervt mich? (Who or what annoys me?) → Der Lärm.

Subjects take the nominative case, so you use der (not den, dem, etc.).

What does im mean, and what is it made of?

im is a contraction of in dem:

in = in
dem = dative singular article for masculine or neuter nouns

So:

in + dem Treppenhaus → im Treppenhaus

It means in the stairwell. The dative (dem) is used because this is a location (where something is), not a direction (where something is going to).

Why is it im Treppenhaus and not in das Treppenhaus?

In German, in can take dative or accusative:

Dative = location (where something/someone is)
Accusative = direction/movement (where something/someone is going)

Here we are talking about where the noise is (its location), not movement:

Wo ist der Lärm? (Where is the noise?) → im Treppenhaus (in the stairwell) → dative

in das Treppenhaus (accusative) would be used for movement:

Ich gehe in das Treppenhaus. = I’m going into the stairwell.

What exactly is a Treppenhaus? How is it different from Treppe?

Treppenhaus is a compound noun:

die Treppe = the (one) staircase / set of stairs
das Haus = the house

das Treppenhaus literally: staircase-house → the stairwell or stairway area of a building (the space where the stairs and landings are, usually in an apartment building or multi-story house).

Difference:

die Treppe: the actual stairs themselves (you walk up a Treppe).
das Treppenhaus: the whole vertical space containing the stairs, usually enclosed, including landings, railings, etc.

In this sentence, im Treppenhaus suggests the noise is somewhere in that stairway area (neighbors talking, doors slamming, kids running, etc.).

What does nervt mich literally mean, and how strong is it?

nervt is the 3rd person singular of nerven. Literally:

nerven = to get on someone’s nerves, to annoy, to bug

So nervt mich = annoys me / gets on my nerves.

Strength and tone:

It’s informal, everyday language.
It can mean anything from is getting on my nerves a bit to really annoys me, depending on tone and context.
It’s weaker than macht mich wahnsinnig (drives me crazy), but stronger than a neutral ich bemerke den Lärm (I notice the noise).

Why is it mich and not mir after nervt?

mich is the accusative form of ich.
mir is the dative form of ich.

The verb nerven takes a direct object in the accusative:

jemanden nerven = to annoy someone

So you say:

Der Lärm nervt mich. = The noise annoys me. (accusative)
Not: Der Lärm nervt mir. (incorrect)

Compare:

Das gefällt mir. → gefallen uses mir (dative).
Das nervt mich. → nerven uses mich (accusative).

You simply have to memorize which verbs take accusative and which take dative.

Can I change the word order and say Mich nervt der Lärm im Treppenhaus or Der Lärm nervt mich im Treppenhaus?

Yes, German word order is flexible, as long as the verb stays in second position in main clauses.

All of these are grammatically correct, but differ in emphasis:

Der Lärm im Treppenhaus nervt mich.
– Neutral order, mild focus on where the noise is.
Mich nervt der Lärm im Treppenhaus.
– Puts emphasis on mich (me):
I am the one who is annoyed (maybe others aren’t).
Der Lärm nervt mich im Treppenhaus.
– Grammatically okay, but slightly odd in this particular sentence.
It sounds like the place where it annoys you is im Treppenhaus (as if it only annoys you there), which is a bit unnatural here.

Standard and clearest version is the original: Der Lärm im Treppenhaus nervt mich.

Is nerven a separable verb? Why doesn’t anything get split here?

nerven is not a separable verb. It’s a simple verb stem:

infinitive: nerven
er/sie/es: nervt

A separable verb would have a prefix that moves to the end, like aufstehen → ich stehe auf.
nerven doesn’t have such a prefix, so nothing splits:

Der Lärm nervt mich.
Der Lärm hat mich genervt.
Der Lärm wird mich nerven.

Could I also say Der Lärm im Treppenhaus stört mich or Der Lärm im Treppenhaus geht mir auf die Nerven? What’s the difference?

Yes, both alternatives are correct, but they have different nuances:

Der Lärm im Treppenhaus stört mich.
- stören = to disturb, to bother, to interrupt
- Slightly more neutral than nerven; focuses on the fact that the noise disturbs you (e.g. when you’re working or sleeping).
Der Lärm im Treppenhaus geht mir auf die Nerven.
- Literally: the noise goes on my nerves
- Stronger and more idiomatic than nervt mich, often very annoyed or fed up.
- Uses mir (dative), because the structure is jemandem auf die Nerven gehen.

Rough scale of emotional intensity (from milder to stronger):

stört mich → nervt mich → geht mir (total) auf die Nerven

How do you pronounce Lärm and Treppenhaus?

Approximate pronunciation in IPA:

Lärm → /lɛʁm/
- ä like e in bed but often a bit more open
- r is the German R, often uvular (in the throat)
- Ends in -rm, both sounds clearly audible
Treppenhaus → /ˈtʁɛpənˌhaʊs/
- Stress on the first part: Trép-pen-house
- e in Trep- like bed
- -en in Treppen is a weak, almost schwa-like sound /ən/
- au like ow in cow

So the whole sentence roughly:
Der Lärm im Treppenhaus nervt mich. → /deːɐ̯ lɛʁm ɪm ˈtʁɛpənˌhaʊs nɛʁft mɪç/

Why is Lärm capitalized in the middle of the sentence?

German capitalizes all nouns, not just the first word of a sentence.

Lärm is a noun → capitalized
Treppenhaus is also a noun → capitalized

So even in the middle of a sentence, nouns must start with a capital letter:
Der Lärm im Treppenhaus nervt mich.

Is Lärm countable in German? Can I say ein Lärm or use it in the plural?

Lärm is usually uncountable in everyday German, similar to noise in English when you mean noise in general:

Es gibt viel Lärm. = There is a lot of noise.
Der Lärm ist unerträglich. = The noise is unbearable.

Using ein Lärm or plural Lärme is very uncommon and would sound strange in normal conversation. You would generally not say:

✗ ein Lärm
✗ mehrere Lärme

If you want to specify types of noise, you usually rephrase, for example:

viele Geräusche (many sounds/noises)
verschiedene Arten von Lärm (different kinds of noise)

Does nervt here refer to a current situation only, or can it also mean something that annoys me regularly?

The German Präsens (present tense) covers both right now and general/habitual meaning, just like in English:

Der Lärm im Treppenhaus nervt mich.
- Could mean: The noise in the stairwell is annoying me (right now).
- Or: The noise in the stairwell always/regularly annoys me.

Context (or added time expressions) tells you which is meant:

Heute nervt mich der Lärm im Treppenhaus. → today (right now)
Jeden Tag nervt mich der Lärm im Treppenhaus. → every day (habitually)