Für die Party kaufe ich eine Ananas und frisches Obst.

German often puts the most important context first. Here, Für die Party sets the scene: it tells us what the shopping is for.

Even though ich is the subject, German still keeps the conjugated verb in second position:

• Für die Party / kaufe / ich / ...

This is a very common pattern in German. You could also say:

• Ich kaufe eine Ananas und frisches Obst für die Party.
• Ich kaufe für die Party eine Ananas und frisches Obst.

All are correct, but they place the emphasis slightly differently.

Because für always takes the accusative case.

The noun Party is feminine, so its article changes like this:

• nominative: die Party
• accusative: die Party

For feminine nouns, die stays die in the accusative, so it looks the same here.

Ananas is a feminine noun in German: die Ananas.

Since it is the direct object of kaufe, it is in the accusative case. The feminine indefinite article in both nominative and accusative is eine:

• nominative: eine Ananas
• accusative: eine Ananas

So eine Ananas is exactly what we expect here.

Because Obst is neuter singular in German: das Obst.

There is no article before Obst here, so the adjective has to carry the grammatical information itself. This is called a strong adjective ending.

For a neuter singular noun in the nominative or accusative with no article, the adjective ending is -es:

• frisches Obst

That is why frisches is correct, not frische.

Because Obst is often used as an uncountable mass noun, like fruit in English.

So frisches Obst means something like:

• fresh fruit
• some fresh fruit

No article is needed when speaking in a general, non-specific way.

If you were talking about a specific fruit selection, you might use an article, for example:

• das frische Obst = the fresh fruit

Grammatically, Obst is usually treated as singular in German, even though it refers to a collection of fruit.

So you say:

• frisches Obst
• das Obst ist lecker

It works more like fruit in English than fruits.

If you want to talk about different kinds of fruit individually, German often uses more specific words instead, such as:

• Früchte = fruits
• Obstsorten = types of fruit

Both are in the accusative case because they are the things being bought.

The verb kaufen usually takes a direct object in the accusative:

• Ich kaufe eine Ananas.
• Ich kaufe frisches Obst.

In this sentence, the speaker is buying two things:

• eine Ananas
• frisches Obst

So both are accusative objects.

Yes, absolutely.

That version is completely natural and has the same basic meaning. The difference is mainly focus:

• Für die Party kaufe ich ... → emphasizes what the shopping is for
• Ich kaufe ... für die Party → more neutral, starts with the subject

German word order is flexible, but the conjugated verb still needs to stay in second position in a main clause.

Because in a German main clause, the finite verb must be in second position.

Since Für die Party has been placed first, the verb must come next:

• Für die Party = position 1
• kaufe = position 2
• ich = after the verb

This often surprises English speakers, because English usually keeps the subject before the verb. In German, if something other than the subject comes first, the subject often moves after the verb.

Because all nouns are capitalized in German.

So in this sentence:

• Party
• Ananas
• Obst

are all capitalized simply because they are nouns. This is a basic rule of German spelling.

Because und is joining two equal items in a simple list:

• eine Ananas
• frisches Obst

In German, just like in English, you normally do not put a comma before und in a simple coordination like this.

It is a loanword from English, but it is fully used in German.

In German, it is:

• die Party

Its pronunciation is German-style, and it follows German grammar rules, including gender, case, and capitalization. This is very common in modern German vocabulary.