Der Toaster funktioniert wieder, weil mein Vater ihn repariert hat.

In German, weil is a subordinating conjunction meaning because. A clause introduced by weil is a subordinate clause, and German normally separates it from the main clause with a comma.

So:

• Der Toaster funktioniert wieder = main clause
• weil mein Vater ihn repariert hat = subordinate clause

That is why the comma is required.

Because weil sends the conjugated verb to the end of its clause.

In a normal main clause, you would say:

• Mein Vater hat ihn repariert.

But after weil, the word order changes:

• weil mein Vater ihn repariert hat

This is one of the most important German word order patterns:

• main clause: conjugated verb usually in position 2
• subordinate clause: verb goes to the end

With the perfect tense, the past participle and the auxiliary verb both move to the end area, with the auxiliary last:

• repariert hat

This is because the clause starts with weil, which creates subordinate-clause word order.

Compare:

• Mein Vater hat ihn repariert.
• ..., weil mein Vater ihn repariert hat.

In subordinate clauses, the verb cluster goes at the end. For the perfect tense, that means:

• past participle first: repariert
• auxiliary last: hat

So repariert hat is correct here.

Because ihn is the accusative form of er.

The toaster is the thing being repaired, so it is the direct object of reparieren. German uses the accusative case for direct objects.

Forms of er:

• er = he
• ihn = him

Here, ihn refers to der Toaster:

• mein Vater ihn repariert hat = my father repaired it/him

Since Toaster is masculine (der Toaster), the accusative pronoun is ihn.

German often uses a pronoun to avoid repeating a noun, just like English does.

Instead of saying:

• ..., weil mein Vater den Toaster repariert hat

the sentence says:

• ..., weil mein Vater ihn repariert hat

Both are correct. Using ihn simply sounds more natural because der Toaster was already mentioned.

Because Toaster is a masculine noun in German, so its nominative singular article is der.

In this sentence, der Toaster is the subject of funktioniert, so it appears in the nominative case:

• der Toaster = the toaster

If it were the direct object, you would see:

• den Toaster

That is why the sentence has Der Toaster funktioniert..., but later the pronoun becomes ihn.

Because mein Vater is the subject of the subordinate clause, so it is in the nominative case.

• mein Vater = my father (subject)
• meinen Vater = my father (direct object)

In weil mein Vater ihn repariert hat, your father is the one doing the action, so nominative is needed:

• mein Vater

Because it is modifying a masculine noun in the nominative singular, and in that pattern the form is simply mein.

• mein Vater = my father
• meinen Vater = my father (accusative masculine)

This is part of how possessive determiners change in German depending on gender, number, and case.

The sentence describes:

1. the current result: The toaster works again
2. the earlier cause: because my father repaired it

So German uses:

• funktioniert = present tense, describing the toaster’s situation now
• hat repariert = perfect tense, describing the earlier repair

This matches the logic of the sentence very well.

In everyday spoken German, the perfect tense is very common for talking about past events.

So Germans usually say:

• Mein Vater hat ihn repariert.

rather than:

• Mein Vater reparierte ihn.

The simple past (Präteritum) is used much more in writing and with certain very common verbs like sein, haben, and modal verbs.

So hat repariert is the natural everyday choice here.

It is the perfect tense of reparieren.

It is made of:

• hat = present tense of haben
• repariert = past participle

So:

• reparieren = to repair
• hat repariert = has repaired / repaired

In natural English, this often just translates as a simple past:

• my father repaired it

Wieder means again, and its position here is very natural in German.

• Der Toaster funktioniert wieder.

This means the toaster is working again now.

German adverb placement is flexible, but this is the most idiomatic version for this sentence. A learner should remember the whole pattern:

• etwas funktioniert wieder = something works again

Yes. In this sentence, wieder means again, as in it works again now.

German wieder can sometimes also mean back, depending on context, but here again is clearly the right interpretation because the idea is that the toaster had stopped working and now works once more.

Because object pronouns usually appear before the final verb cluster in a subordinate clause.

So in:

• weil mein Vater ihn repariert hat

the order is:

• weil
• subject: mein Vater
• object pronoun: ihn
• verb cluster at the end: repariert hat

This is a very common German pattern.

Yes, absolutely.

That version repeats the noun instead of using a pronoun:

• Der Toaster funktioniert wieder, weil mein Vater den Toaster repariert hat.

It is grammatically correct, but stylistically a bit repetitive. Native speakers would usually prefer:

• ..., weil mein Vater ihn repariert hat.

Yes. You can say:

• Weil mein Vater ihn repariert hat, funktioniert der Toaster wieder.

That is also correct.

When the subordinate clause comes first, the main clause still follows the normal rule that the conjugated verb comes early, and the first position of the main clause is already occupied by the whole weil clause. That is why you get:

• ..., funktioniert der Toaster wieder not
• ..., der Toaster funktioniert wieder

In German, all nouns are capitalized.

So in this sentence:

• Toaster
• Vater

both begin with capital letters because they are nouns. This is a standard rule in German spelling.