Η καφετιέρα δεν δουλεύει καλά σήμερα, οπότε έφτιαξα ελληνικό καφέ.

Η is the feminine singular definite article, meaning the.

• η καφετιέρα = the coffee maker
• καφετιέρα is a feminine noun, so it takes η in the nominative singular.

Greek usually uses the definite article more often than English, so seeing η here is completely normal.

Καφετιέρα means coffee maker or coffee machine, especially a home appliance for making coffee.

It is a common everyday word in Modern Greek. In this sentence, it clearly refers to the machine not working properly.

Δουλεύει literally means works or is working. With machines, Greek often uses δουλεύω just like English uses work:

• Η καφετιέρα δουλεύει. = The coffee maker works / is working.
• Η τηλεόραση δεν δουλεύει. = The TV doesn’t work.

So δεν δουλεύει means doesn’t work or isn’t working.

In Greek, δεν is the normal negation word used with verbs in the indicative. It comes directly before the verb:

• δουλεύει = it works
• δεν δουλεύει = it doesn’t work

That placement is very standard in Greek.

Καλά means well here. It is an adverb modifying δουλεύει:

• δουλεύει καλά = works well
• δεν δουλεύει καλά = doesn’t work well

So the sentence is not necessarily saying the machine is completely broken. It may just be malfunctioning or performing badly.

Yes, σήμερα means today, and it often suggests that this is the situation today, not necessarily always.

• Η καφετιέρα δεν δουλεύει καλά σήμερα = The coffee maker isn’t working well today

That can imply a temporary problem: maybe just today the machine is acting up.

In Greek, σήμερα can appear in different positions, but here it sounds very natural at the end of the clause.

Οπότε means so, therefore, or which is why in this sentence.

It connects the first idea to the result:

• Η καφετιέρα δεν δουλεύει καλά σήμερα = cause
• οπότε έφτιαξα ελληνικό καφέ = result

So:

• ..., οπότε έφτιαξα... = ..., so I made...

It is very common in spoken and everyday Greek.

Έφτιαξα is the aorist (simple past) of φτιάχνω, which means make, prepare, fix, depending on context.

Here it means I made / I prepared:

• φτιάχνω καφέ = I make coffee
• έφτιαξα καφέ = I made coffee

The aorist is used because this is a completed action in the past: the speaker made the coffee.

Because ελληνικό καφέ is the accusative singular, not the nominative.

After έφτιαξα (I made), the coffee is the direct object, so Greek uses the accusative:

• nominative: ο ελληνικός καφές = Greek coffee
• accusative: τον ελληνικό καφέ = Greek coffee as an object

In this sentence, there is no article, so we get:

• έφτιαξα ελληνικό καφέ = I made Greek coffee

So:

• ελληνικό is the masculine accusative singular form of the adjective
• καφέ is the accusative singular of καφές

Greek can leave out the article when talking about something indefinite or when referring to a substance/food/drink in a general way.

So:

• έφτιαξα ελληνικό καφέ = I made Greek coffee
• έφτιαξα έναν ελληνικό καφέ would mean something more like I made a Greek coffee / one Greek coffee

Both are possible, but without the article it sounds very natural for talking about preparing some coffee.

No. Here ελληνικό means Greek as an adjective describing the type of coffee.

So:

• ελληνικός καφές / ελληνικό καφέ = Greek coffee

It does not mean the word coffee in Greek. It refers to the beverage/style of preparation.

Yes, absolutely. Greek uses δουλεύω for both people and machines.

Examples:

• Δουλεύω σήμερα. = I’m working today.
• Το πλυντήριο δεν δουλεύει. = The washing machine doesn’t work.
• Ο υπολογιστής δουλεύει καλά. = The computer works well.

So its use with καφετιέρα is completely natural.

Because οπότε introduces the result of the first clause, and Greek normally separates these clauses with a comma:

• Η καφετιέρα δεν δουλεύει καλά σήμερα, οπότε...

This is similar to English punctuation in:

• The coffee maker isn’t working well today, so...

So the comma helps show the pause and the cause-result relationship.

Yes. λειτουργεί also means functions / operates.

So both are possible:

• Η καφετιέρα δεν δουλεύει καλά σήμερα
• Η καφετιέρα δεν λειτουργεί καλά σήμερα

The difference is mostly in tone:

• δουλεύει is more everyday and conversational
• λειτουργεί is a bit more formal or technical

In normal speech, δουλεύει is very common.