Ako me budilica ne probudi, doći ću kasno na posao.

Croatian does not have articles like English a/an and the.

So:

• budilica can mean an alarm clock or the alarm clock
• posao can mean a job/work or the job/work

Context tells you which meaning is intended. In this sentence, English naturally uses the alarm clock and work, but Croatian simply says budilica and posao.

Me means me.

It is the short unstressed accusative form of the pronoun ja (I).

Here, the verb probuditi means to wake someone up, so the person being woken is the direct object:

• budilica probudi mene = the alarm wakes me up

In normal speech, Croatian usually uses the short clitic form me, not mene, unless you want emphasis:

• Ako me budilica ne probudi... = neutral
• Ako mene budilica ne probudi... = more emphatic, like if the alarm doesn’t wake me.

Because me is a clitic. Croatian clitics usually go in the second position in their clause.

In this sentence, the clause starts with Ako, so the clitic me comes right after it:

• Ako me budilica ne probudi...

This is very normal Croatian word order.

A more English-like order such as Ako budilica me ne probudi sounds wrong in standard Croatian because the clitic is not in its usual position.

After ako (if), Croatian usually uses the present tense for a future condition, not a future form.

So Croatian says:

• Ako me budilica ne probudi...

even though in English the meaning is future:

• If the alarm doesn’t wake me up...

This is actually similar to English, which also says If it rains, I’ll stay home, not If it will rain.

In Croatian, Ako me budilica neće probuditi would not be the normal way to say this.

This is about aspect, which is very important in Croatian.

• buditi = imperfective verb, focusing on an ongoing, repeated, or habitual action
• probuditi = perfective verb, focusing on a completed single event: to wake someone up

Here the speaker means one specific event in the future: whether the alarm will succeed in waking them up. So Croatian uses the perfective verb:

• Ako me budilica ne probudi...

The form probudi is the 3rd person singular present of probuditi.

Yes. Grammatically, it is a present-tense form, but because it follows ako and comes from a perfective verb, it refers to a future completed event.

So literally it looks present, but in meaning it is future:

• Ako me budilica ne probudi... = If the alarm doesn’t wake me up...

This is a very common Croatian pattern.

Doći ću is the future tense (future I) of doći = to come / to arrive.

It is made from:

• the infinitive doći
• the clitic form ću = I will

So:

• doći ću = I will come / I will arrive

It is written as two words.

A useful spelling rule:

• with many infinitives ending in -ti, the final -i drops before ću:
  
  • raditi → radit ću
  • pisati → pisat ću
• but with verbs ending in -ći, nothing is dropped:
  
  • doći ću
  • reći ću

You can also put the future auxiliary before the infinitive:

• Ja ću doći

Both are correct.

Because kasno is an adverb, and it modifies the verb doći.

• kasno = late (adverb)
• kasni / kasna / kasno = late (adjective forms, used to describe a noun)

Here the meaning is:

• doći kasno = to arrive late

Compare:

• kasni vlak = a late train
  Here kasni is an adjective describing vlak.

Because na posao expresses movement toward a destination.

• na posao = to work / to the workplace
• na poslu = at work (location, not movement)

So:

• doći na posao = to come to work
• biti na poslu = to be at work

U posao would not fit here. It would suggest something like into the work/business, not the normal idea of going to work.

Also note the case difference:

• na posao = accusative after motion
• na poslu = locative after location

To some extent, yes. Croatian word order is more flexible than English word order.

For example, you could also say:

• Ako me budilica ne probudi, kasno ću doći na posao.

This shifts the emphasis a bit toward kasno.

But the freedom is not unlimited. Clitics such as me and ću still have placement rules, so you cannot move them around freely the way you might move full words.

Because the sentence begins with a subordinate conditional clause:

• Ako me budilica ne probudi = the if-clause

Then comes the main clause:

• doći ću kasno na posao

In Croatian, when the dependent clause comes first, it is normally separated by a comma:

• Ako me budilica ne probudi, doći ću kasno na posao.

This is similar to English:

• If the alarm doesn’t wake me up, I’ll be late for work.

A rough pronunciation guide is:

• doći ≈ DO-chee, but with a softer sound than English ch
• ću ≈ tyoo or a very soft choo

The letter ć is a soft consonant. English does not have an exact equivalent. It is softer than č.

So:

• č is harder, more like English ch
• ć is softer, somewhat between t
  • y and ch

Learners often find doći ću tricky because it contains ć twice in a row across two words. The best approach is to listen to native audio and imitate it.