Mijn fietsbel doet het niet, dus ik zeg liever “pas op” tegen een voetganger.

Doet het niet is a very common Dutch way to say that something is not working.

So:

• Mijn fietsbel doet het niet = My bike bell isn’t working

Dutch often uses het doen for devices, machines, lights, buttons, bells, and similar things:

• De tv doet het niet = The TV isn’t working
• Mijn telefoon doet het niet = My phone isn’t working

You can also say werkt niet in some cases, but doet het niet is especially idiomatic for everyday spoken Dutch.

In doet het niet, the het does not translate very neatly into English. It is part of the fixed expression het doen = to work / to function.

So you should learn:

• iets doet het = something works
• iets doet het niet = something doesn’t work

The het does not mean it in a very literal, point-by-point way. It is just part of the standard phrase.

Dutch forms compound nouns very often, much more freely than English does.

• fiets = bicycle
• bel = bell
• fietsbel = bicycle bell / bike bell

This is completely normal in Dutch. English might write similar ideas as two words, with a hyphen, or as one word depending on the noun, but Dutch usually joins them into one compound noun.

Other examples:

• treinstation = train station
• huisdeur = house door / front door
• regenjas = raincoat

Yes. Mijn fietsbel is the subject of the first clause:

• Mijn = my
• fietsbel = bike bell

So:

• Mijn fietsbel doet het niet = My bike bell doesn’t work

Dutch possessives like mijn, jouw, zijn, haar, ons, hun work a lot like English my, your, his, her, our, their.

Dutch main clauses normally follow the verb-second rule. That means the finite verb comes in the second position of the clause.

In the clause:

• Mijn fietsbel = first position
• doet = finite verb, so it comes second
• het niet = the rest

So:

• Mijn fietsbel doet het niet

This is standard Dutch word order.

If you started with another element, the verb would still come second:

• Vandaag doet mijn fietsbel het niet = Today my bike bell isn’t working

Dus means so or therefore.

It connects the first idea to the second:

• Mijn fietsbel doet het niet, dus ik zeg liever ...
• My bike bell doesn’t work, so I’d rather say ...

Its position here is very natural: it introduces the consequence.

After dus, the next clause follows normal Dutch main-clause word order:

• ik = subject
• zeg = finite verb

So:

• dus ik zeg liever ...

Liever means rather or preferably.

In this sentence:

• ik zeg liever ... = I’d rather say ...

It is related to preference:

• Ik fiets liever dan ik loop = I prefer cycling to walking
• Ik drink liever thee = I’d rather drink tea

A useful pair is:

• graag = gladly / with pleasure / like
• liever = rather / prefer

For example:

• Ik drink graag koffie = I like drinking coffee
• Ik drink liever koffie dan thee = I prefer coffee to tea

Because Dutch main clauses keep the finite verb in second position.

In the second clause:

• ik = first position
• zeg = finite verb, so it must come second
• liever = adverb
• pas op = what is said
• tegen een voetganger = to a pedestrian

So the order is:

• ik zeg liever pas op tegen een voetganger

This is normal Dutch word order.

Pas op is a fixed Dutch warning meaning watch out, be careful, or look out.

It comes from the verb oppassen in the imperative form:

• pas op! = watch out!

Even though the dictionary form is oppassen, the imperative is usually split:

• Pas op!

This is very common with Dutch separable verbs.

Examples:

• opstaan → Sta op! = Get up!
• meekomen → Kom mee! = Come along!
• uitkijken → Kijk uit! = Watch out!

So pas op should be learned as a fixed warning expression.

Because the sentence is mentioning the exact words the speaker would say.

So the structure is:

• ik zeg liever pas op = I’d rather say watch out

When a sentence refers to the actual words spoken, Dutch often marks them off the same way English does. In normal writing, quotation marks are common, but if you are avoiding quotation marks, it makes sense to highlight the phrase typographically.

With zeggen, Dutch often uses tegen to mark the person you are saying something to.

• iets zeggen tegen iemand = to say something to someone

So:

• ik zeg pas op tegen een voetganger = I say watch out to a pedestrian

Examples:

• Ik zei het tegen mijn broer = I said it to my brother
• Wat heb je tegen haar gezegd? = What did you say to her?

English learners sometimes expect something closer to aan, but with zeggen, tegen is very common.

Een voetganger means a pedestrian. Here it is being used in a general sense: to a pedestrian, to any pedestrian.

So the sentence means something like:

• when dealing with a pedestrian, I’d rather say pas op

Dutch often uses the singular with een in examples like this when talking about a typical member of a group.

You could also make it plural in another context:

• tegen voetgangers = to pedestrians

But tegen een voetganger sounds perfectly natural here.

Yes, you can, and it would be understood.

• Mijn fietsbel werkt niet = My bike bell doesn’t work

But doet het niet is very idiomatic and conversational. It sounds especially natural for something mechanical or electronic that is failing to function.

So both are possible, but:

• doet het niet = very everyday, natural spoken Dutch
• werkt niet = also correct, a bit more direct or neutral

Yes, depending on the situation.

• zeggen = say
• roepen = call out / shout

If you are warning a pedestrian while riding a bike, roepen may even sound very realistic:

• ... dus ik roep liever pas op tegen een voetganger

That suggests actually calling it out loudly.
The original with zeggen is still fine, though, because Dutch often uses zeggen in a broad way for speaking.

Yes, it is natural and understandable.

A Dutch speaker might also say things like:

• Mijn bel doet het niet, dus ik roep liever pas op.
• Mijn fietsbel werkt niet, dus dan zeg ik liever pas op tegen voetgangers.

But the original sentence is good Dutch and uses several very common patterns:

• X doet het niet
• dus
• liever
• pas op
• iets zeggen tegen iemand