Als ik haast heb, wordt mijn handschrift zo klein dat het bijna niet meer leesbaar is.

Because als introduces a subordinate clause. In Dutch subordinate clauses, the conjugated verb usually goes to the end.

So:

• Ik heb haast. = main clause
• Als ik haast heb, ... = subordinate clause

This is very common in Dutch:

• Omdat ik moe ben = because I am tired
• Als hij komt = if/when he comes

So heb moves to the end because of als.

Haast hebben is a fixed expression meaning to be in a hurry.

Literally, it looks like to have haste, which is similar to older or more formal English phrasing. Dutch often uses hebben in expressions where English uses to be.

Examples:

• Ik heb haast. = I am in a hurry.
• Heb je haast? = Are you in a hurry?

So in this sentence, Als ik haast heb means When/If I’m in a hurry.

Wordt is from worden, which often means to become.

Here, the sentence is saying that the handwriting becomes so small, not that it simply is small all the time.

• Mijn handschrift is klein. = My handwriting is small.
• Mijn handschrift wordt klein. = My handwriting becomes small.

So wordt is used because the handwriting changes when the speaker is in a hurry.

Handschrift is the normal Dutch noun for handwriting.

It is made up of:

• hand = hand
• schrift = writing/script

So mijn handschrift means my handwriting.

Schrijven is the verb to write, not the usual noun for someone’s handwriting style.

Zo ... dat ... means so ... that ....

In this sentence:

• zo klein = so small
• dat het bijna niet meer leesbaar is = that it is almost no longer readable

This structure is very common in Dutch:

• Hij is zo moe dat hij meteen slaapt. = He is so tired that he falls asleep immediately.
• Het is zo koud dat ik binnen blijf. = It is so cold that I stay inside.

So zo klein dat works just like English so small that.

Het refers to mijn handschrift.

Even though handschrift is translated as handwriting, it is a het-word in Dutch. That means when you refer back to it, you use het.

So:

• het handschrift
• mijn handschrift
• het ... is leesbaar

That is why the sentence says dat het ... leesbaar is.

Niet meer means no longer or not anymore.

So:

• leesbaar = readable
• niet meer leesbaar = no longer readable

In the full sentence:

• bijna niet meer leesbaar = almost no longer readable / almost not readable anymore

This is a very common Dutch expression:

• Ik woon daar niet meer. = I no longer live there.
• Hij werkt hier niet meer. = He doesn’t work here anymore.

Bijna means almost, and here it modifies the whole idea not readable anymore.

So:

• bijna niet meer leesbaar = almost no longer readable

The word order is natural Dutch. Bijna often comes before the part it affects:

• bijna klaar = almost ready
• bijna te laat = almost too late
• bijna niet meer leesbaar = almost no longer readable

It would sound unnatural to place bijna much later in this clause.

Again, this is because dat introduces a subordinate clause, and in Dutch subordinate clauses the verb usually goes to the end.

Compare:

• Main clause: Het is leesbaar.
• Subordinate clause: dat het leesbaar is

So in:

dat het bijna niet meer leesbaar is

the verb is comes at the end because the whole clause is introduced by dat.

Leesbaar means readable.

It comes from:

• lezen = to read
• -baar = a suffix meaning something like -able

So:

• leesbaar = readable
• eetbaar = edible
• zichtbaar = visible
• betaalbaar = affordable

This is a useful pattern in Dutch.

It can feel like either if or when, depending on context.

• Als ik haast heb can mean If I’m in a hurry
• It can also feel like When I’m in a hurry

In this sentence, it expresses a general situation: whenever the speaker is in a hurry, their handwriting gets very small. So in natural English, when may sound slightly smoother, but if is also possible depending on interpretation.

Yes, in standard Dutch spelling, a subordinate clause at the beginning of the sentence is normally followed by a comma before the main clause.

So:

• Als ik haast heb, wordt mijn handschrift ...

This is similar to English, where an introductory clause is also often followed by a comma:

• When I’m in a hurry, my handwriting becomes ...

Yes, you could.

• Als ik haast heb = If/when I’m in a hurry
• Wanneer ik haast heb = When I’m in a hurry

In many cases, als is more common and more conversational for this kind of sentence. Wanneer can sound a bit more explicit or slightly more formal, but it is perfectly correct.

The sentence has three parts:

1. Als ik haast heb
   A subordinate clause introduced by als

2. wordt mijn handschrift zo klein
   The main clause

3. dat het bijna niet meer leesbaar is
   Another subordinate clause introduced by dat

So the pattern is:

• [subordinate clause], [main clause] + zo ... dat [subordinate clause]

This makes it a very useful example of Dutch word order, because it shows both:

• verb-final order in subordinate clauses
• normal main-clause order after an introductory clause, where the verb comes before the subject: wordt mijn handschrift rather than mijn handschrift wordt

That happens because the first position in the sentence is already occupied by Als ik haast heb.