Als het regent, fiets ik langzamer, want de weg is glad.

Here als can be understood as if or when, depending on context.

In this sentence, it introduces a general condition:

• Als het regent, fiets ik langzamer = If/When it rains, I cycle more slowly

Dutch often uses als for things like:

• general truths
• repeated situations
• conditions

A native English speaker may expect a strict difference between if and when, but Dutch als often covers both in sentences like this.

You could also see wanneer, but als is very common and natural here.

In het regent, het is an impersonal subject. It does not refer to a real thing.

This is very similar to English it is raining or it rains, where it also does not mean a specific object.

Dutch uses het with weather verbs such as:

• het regent = it is raining
• het sneeuwt = it is snowing
• het waait = it is windy / the wind is blowing

So in this sentence, het is just the normal grammatical subject required by the verb.

Because als introduces a subordinate clause.

In Dutch, subordinate clauses usually send the finite verb to the end. So:

• main clause: Het regent
• subordinate clause: als het regent

That is a very important Dutch word-order pattern:

• dat
  • subject + ... + verb
• omdat
  • subject + ... + verb
• als
  • subject + ... + verb

So Als het regent follows the normal subordinate-clause structure.

This is because Dutch main clauses normally follow the verb-second rule.

The first part, Als het regent, takes up the first position in the sentence. That means the finite verb of the main clause must come next, in second position:

• Als het regent, fiets ik langzamer.

Structure:

• Position 1: Als het regent
• Position 2: fiets
• then subject: ik

If the sentence started directly with the subject, then you would get:

• Ik fiets langzamer als het regent.

That is also possible, but the original sentence puts the condition first for emphasis.

Because langzamer means more slowly or slower, while langzaam means slowly or slow.

Compare:

• Ik fiets langzaam. = I cycle slowly.
• Ik fiets langzamer. = I cycle more slowly / slower.

In this sentence, the idea is comparative: when it rains, I ride at a lower speed than usual.

Also, Dutch often uses the same form for adjectives and adverbs, so langzamer can work adverbially here even though in English we often prefer more slowly.

Here it functions adverbially, because it describes how I cycle.

It is modifying the verb fiets, not a noun.

So:

• een langzamere fiets would be adjective-like: a slower bike
• ik fiets langzamer is adverbial: I cycle more slowly

Dutch does not always mark adjectives and adverbs differently the way English does.

That is a very common question, because Dutch has two different ways to say because:

1. want
2. omdat

They behave differently.

With want

Want is a coordinating conjunction, so the clause after it keeps main-clause word order:

• want de weg is glad

With omdat

Omdat introduces a subordinate clause, so the verb goes to the end:

• omdat de weg glad is

So both of these are possible:

• Als het regent, fiets ik langzamer, want de weg is glad.
• Als het regent, fiets ik langzamer, omdat de weg glad is.

Both mean basically the same thing, but the grammar after them is different.

Both can mean because, but they are not always used in exactly the same way.

want

• links two main clauses
• often sounds like an added explanation
• keeps normal word order

Example:

• ..., want de weg is glad.

omdat

• introduces a subordinate clause
• often presents the reason more tightly as part of the sentence
• sends the verb to the end

Example:

• ..., omdat de weg glad is.

In everyday speech, both are common. A learner mainly needs to remember the word-order difference.

No. This is a classic false friend.

In Dutch, glad usually means:

• smooth
• slippery

So:

• de weg is glad = the road is slippery

If you want to say happy in Dutch, the usual word is blij:

• Ik ben blij. = I am happy.

So do not read Dutch glad as English glad in this sentence.

Because weg is a de-word in Dutch.

So the correct article is:

• de weg = the road

This is something you usually have to learn with each noun, because Dutch nouns take either de or het.

A useful thing to remember:

• de weg
• plural: de wegen

There are two commas for structural reasons.

1. After Als het regent

A subordinate clause placed before the main clause is normally followed by a comma:

• Als het regent, fiets ik langzamer.

2. Before want

A comma is very commonly used before want when it introduces an explanatory clause:

• ..., want de weg is glad.

So the punctuation helps show the sentence structure clearly.

Yes, absolutely.

That version is also correct:

• Ik fiets langzamer als het regent.

The difference is mainly focus:

• Als het regent, fiets ik langzamer puts the condition first
• Ik fiets langzamer als het regent starts with the main statement

Both are natural. The original sentence just emphasizes the rainy condition first.

Fiets is the present tense of fietsen.

The sentence uses the present tense because it describes a habitual or general situation:

• whenever it rains, I ride more slowly

Dutch, like English, often uses the present tense for things that are generally true or regularly happen.

So this is not necessarily about what is happening right now; it can describe your usual behavior.