Mijn rem werkt niet goed, daarom fiets ik vandaag langzamer.

Rem is singular: the brake. In everyday Dutch, the singular can refer to one brake or even the braking system in a general way.

If you want to be very explicit that you mean both brakes, you can say mijn remmen. But mijn rem werkt niet goed sounds natural if the speaker is talking about a braking problem in general.

Literally, werkt niet goed means doesn’t work well.

• werkt = works
• niet = not
• goed = well / properly

So the idea is that the brake is not functioning properly, not necessarily that it is completely broken. If it were completely unusable, Dutch might also say Mijn rem werkt niet.

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

That means the finite verb must come in the second position. If daarom is placed first, the verb has to come next:

• Daarom fiets ik vandaag langzamer.

So the order is:

1. Daarom
2. fiets
3. ik

This is called inversion. In a neutral clause without daarom in first position, you would get:

• Ik fiets vandaag langzamer.

They are related, but they are used differently.

• daarom = therefore / that is why / for that reason
• omdat = because

With daarom, you usually have two main clauses:

• Mijn rem werkt niet goed, daarom fiets ik vandaag langzamer.

With omdat, you introduce a subordinate clause, and the verb goes to the end:

• Ik fiets vandaag langzamer, omdat mijn rem niet goed werkt.

So both can express the same idea, but the grammar is different.

Dutch fiets can be:

• a noun: de fiets = the bicycle
• a verb form: ik fiets = I cycle / I am cycling

In this sentence, fiets is the verb from fietsen.

Because of inversion after daarom, the verb comes before the subject:

• Daarom fiets ik ...

So here fiets definitely means cycle.

Langzamer is the comparative form: slower.

• langzaam = slow / slowly
• langzamer = slower / more slowly

The sentence implies a comparison, usually with the speaker’s normal speed. In other words, today I am cycling more slowly than usual.

If you said Ik fiets vandaag langzaam, that would just mean I am cycling slowly today, without clearly comparing it to another speed.

Dutch adverb placement is flexible, but this order is very natural.

• vandaag = time
• langzamer = manner/comparison

In Daarom fiets ik vandaag langzamer, vandaag helps set the time frame first, and then langzamer tells us how the speaker is cycling.

Other orders are sometimes possible, but this version sounds smooth and standard. Putting vandaag here also gives it a mild emphasis: today, because of the brake problem, the speaker is cycling more slowly.

The comma separates two main clauses:

• Mijn rem werkt niet goed
• daarom fiets ik vandaag langzamer

In English, you would often split this into two sentences or use a connector such as so or therefore. Dutch often uses a comma before linking the result clause with daarom.

So the comma helps show the logical break: first the problem, then the consequence.

Here goed functions adverbially, because it describes how the brake works.

Compare:

• een goede rem = a good brake → adjective
• de rem werkt goed = the brake works well → adverb-like use

Dutch often uses goed where English would use well. That is very normal in Dutch.