Learn Hardcore German: Der Weg im Park ist rutschig, deshalb gehen wir langsam. - The path in the park is slippery, therefore we walk slowly.

In the sentence Der Weg im Park ist rutschig, Weg is the subject of the sentence, so it appears in the nominative case. The nominative masculine singular definite article is der, so we say der Weg.

You could not say die Weg or das Weg, because that would give the noun the wrong gender.

Why im Park and not in dem Park or in den Park?

im is a standard contraction in German:

im = in dem (in + the, dative masculine/neuter)

So im Park literally means in the park.

Why dem (dative) and not den (accusative)?

Use dative after in when you talk about a location (where something is).
Use accusative after in when you talk about movement into something (where something is going to).

Here we talk about where the path is:

Der Weg ist im Park. – The path is in the park. (location → dative: im = in dem)
If it were movement: Wir gehen in den Park. – We are going into the park. (movement → accusative: in den)

Why is there a comma before deshalb?

Deshalb begins a new main clause. The sentence actually consists of two main clauses:

Der Weg im Park ist rutschig
deshalb gehen wir langsam

In German, when you connect two main clauses with a comma and a connector like deshalb, trotzdem, dann, etc., you normally put a comma between them.

So:

Der Weg im Park ist rutschig, deshalb gehen wir langsam.

Each part could stand alone as a full sentence:

Der Weg im Park ist rutschig.
Deshalb gehen wir langsam.

Why is the word order deshalb gehen wir langsam and not deshalb wir gehen langsam?

German main clauses generally follow the verb-second (V2) rule: the conjugated verb must be in second position.

In deshalb gehen wir langsam:

1st position: deshalb (a sentence adverb)
2nd position: gehen (the conjugated verb)
Rest: wir langsam

So the order deshalb gehen wir langsam is correct.

You cannot say deshalb wir gehen langsam, because then the verb (gehen) would not be in the second position anymore, breaking the V2 rule.

Compare:

Wir gehen langsam. (subject in first position, verb in second)
Heute gehen wir langsam. (adverb in first, verb still in second)
Deshalb gehen wir langsam. (connector/adverb in first, verb still in second)

What is the difference between deshalb and weil here?

Both express a reason, but they work differently in the sentence and change word order:

With deshalb (a so‑called causal adverb):
- Der Weg im Park ist rutschig, deshalb gehen wir langsam.
- Both parts are main clauses.
- The clause after deshalb keeps main‑clause word order (verb second).
With weil (a subordinating conjunction):
- Wir gehen langsam, weil der Weg im Park rutschig ist.
- The weil‑clause is a subordinate clause.
- In a subordinate clause, the conjugated verb goes to the end: … weil der Weg im Park rutschig ist.

Meaning-wise, both versions say essentially the same thing: the path is slippery, and that is the reason we walk slowly. The difference is style and structure, not basic meaning.

Why is it rutschig and not something like rutschiger or rutschigen?

Rutschig is used here as a predicate adjective after the verb ist (sein).

In German:

When an adjective comes after the verb sein, werden, bleiben, etc. (as a predicate), it does not add endings:
- Der Weg ist rutschig.
- Die Straße ist rutschig.
- Die Wege sind rutschig.

No endings are added in these predicate positions, regardless of gender or number.

You only add endings (-er, -en, -e, -es, -em, etc.) when the adjective stands directly before a noun (attributive position):

Der rutschige Weg (the slippery path)
Die rutschigen Wege (the slippery paths)
Auf dem rutschigen Weg (on the slippery path)

So:

Der Weg ist rutschig. (predicate → no ending)
But: Der rutschige Weg ist gefährlich. (before a noun → needs an ending)

Why do we say wir gehen langsam and not wir gehen langsame?

In German, the adverb form of most adjectives is identical to the basic adjective form:

langsam = slow / slowly
schnell = fast / quickly
vorsichtig = careful / carefully

You only add endings (-e, -en, -er, etc.) to adjectives used before a noun. But when an adjective is used as an adverb (describing how you do something), it stays in its basic form:

Wir gehen langsam. – We walk slowly. (adverb → basic form)
Ein langsamer Weg – a slow path (adjective before noun → needs an ending: langsamer)

So langsame would be used only if it came directly before a noun and the grammar required that ending, for example:

die langsame Musik – the slow music

Here we just modify the verb gehen, so langsam is correct.

In English we say “We are walking slowly.” Why is it just wir gehen in German and not something like “wir sind gehen”?

German normally uses the simple present tense for both:

English I walk and I am walking
German ich gehe

There is no general, everyday progressive form built with sein + gehen the way English does with to be + -ing.

So:

Wir gehen langsam. can mean:
- We walk slowly.
- We are walking slowly.

Context decides which English translation is better, but the German form is the same.

Could we use a different word instead of rutschig, like glatt?

Yes, there are a few possible adjectives here, with slightly different nuances:

rutschig – slippery, easy to slip on; focuses on the danger of slipping.
glatt – smooth; can also imply slippery (especially with ice), but literally refers more to the smooth surface.
schlüpfrig – slippery, but often used more figuratively or sounds more unusual for a path in everyday language.

All of these are grammatically fine:

Der Weg im Park ist rutschig.
Der Weg im Park ist glatt.

But rutschig is the most direct and common when you want to say it is easy to slip there.

Why is it Der Weg (nominative) and not Den Weg or Dem Weg at the beginning?

At the beginning of the sentence, Der Weg is the subject of the sentence – the thing that is slippery.

Subjects in German take the nominative case. The nominative masculine singular definite article is der.

Der Weg ist rutschig. – The path is slippery. (subject → nominative → der Weg)

The other forms would be used for different functions:

den Weg – accusative (direct object), e.g. Ich sehe den Weg.
dem Weg – dative (indirect object / after certain prepositions), e.g. Auf dem Weg ist Eis.

Here, since Weg is simply the subject doing nothing but “being” slippery, we need Der Weg.