برای آن جشن میخواهیم یک کیک بزرگ بخریم.

Persian normally prefers subject/object/verb word order, so the main action often comes at the end.

In this sentence:

• برای آن جشن = for that party/celebration
• یک کیک بزرگ = a big cake
• می‌خواهیم = we want
• بخریم = buy

So the sentence is structured roughly like:

For that party, we want a big cake to buy
but in natural English we say: We want to buy a big cake for that party.

Persian is flexible, but putting the verb at the end is very common and natural.

برای means for.
آن جشن means that celebration/party.

So برای آن جشن literally means for that celebration or for that party.

A learner might expect something more like for the party, but Persian often uses آن (that) where English might simply use the, depending on context.

آن literally means that. In many contexts, it really does point to something specific: that party.

But in translation, English may sometimes use the instead, especially if both speakers already know which event is being discussed.

So:

• آن جشن = that celebration
• in context, it may feel like the celebration/the party

In everyday spoken Persian, people often say اون جشن instead of آن جشن.

یک can mean both one and a/an, depending on context.

Here, یک کیک بزرگ means a big cake, not necessarily one big cake in an emphasized counting sense.

So:

• یک کتاب = a book / one book
• یک کیک بزرگ = a big cake

In casual speech, یک is often pronounced and written as یه:

• یه کیک بزرگ

In Persian, adjectives usually come after the noun they describe.

So:

• کیک بزرگ = big cake
• literally: cake big

This is normal Persian word order.

More examples:

• خانه کوچک = small house
• ماشین جدید = new car

If you want to be extra precise grammatically, Persian often links noun and adjective with an ezafe sound in pronunciation:

• کیکِ بزرگ

In normal writing, that short -e/-ye sound is usually not written.

می‌خواهیم means we want.

It comes from the verb خواستن = to want.

Breakdown:

• می‌- = present/imperfective marker
• خواه = verb stem
• -یم = we

So می‌خواهیم = we want

Persian verbs often include the subject inside the verb ending, so you do not need a separate word for we unless you want emphasis.

For example:

• می‌خواهم = I want
• می‌خواهی = you want
• می‌خواهد = he/she wants
• می‌خواهیم = we want

After خواستن (to want), Persian usually uses the subjunctive/present subjunctive form of the next verb.

So:

• می‌خواهیم بخریم = we want to buy

Here, بخریم is the correct form after می‌خواهیم.

Why not the others?

• می‌خریم = we buy / we are buying
• خریدن = to buy (dictionary/infinitive form)

English says want to buy, but Persian says want + subjunctive verb.

That is why بخریم is used.

No separate word is needed here.

English uses to:

• we want to buy

Persian does not insert a separate equivalent in this structure:

• می‌خواهیم بخریم

So the pattern is:

• می‌خواهم بروم = I want to go
• می‌خواهند بخورند = they want to eat
• می‌خواهیم بخریم = we want to buy

This is a very common thing English speakers need to get used to.

The more standard modern spelling is می‌خواهیم with a half-space (called a zero-width non-joiner).

So formally, you will usually see:

• می‌خواهیم

But many texts, messages, and informal writing may show:

• میخواهیم

Both are understood, but می‌خواهیم is the better standard spelling.

The same applies to many Persian verbs with می:

• می‌خریم
• می‌رویم
• می‌دانم

This version sounds fairly neutral to written.

A more conversational spoken version would often be:

• برای اون جشن می‌خوایم یه کیک بزرگ بخریم.

Changes:

• آن → اون = that
• می‌خواهیم → می‌خوایم = we want
• یک → یه = a

The original sentence is absolutely correct, but in everyday speech many people would use the more casual version.

Yes. Persian allows some flexibility, especially when context is clear.

For example, you could also say:

• می‌خواهیم برای آن جشن یک کیک بزرگ بخریم.

This may feel a bit more natural to an English speaker because the want part appears earlier.

Both are grammatical. The original sentence puts extra emphasis or focus on for that party by placing it first.

No, not usually.

The ending -یم in می‌خواهیم already tells you the subject is we.

So:

• می‌خواهیم یک کیک بزرگ بخریم = we want to buy a big cake

If you add ما, it gives emphasis or clarity:

• ما می‌خواهیم یک کیک بزرگ بخریم = we want to buy a big cake

Persian often drops subject pronouns when the verb already makes the subject clear.

A natural pronunciation would be close to:

barâye ân jashn mikhâhim yek keyk-e bozorg bekharim

A few helpful notes:

• برای = barâye
• آن = ân
• جشن = jashn
• کیک = keyk
• بزرگ = bozorg
• بخریم = bekharim

In connected speech, the ezafe after کیک is heard:

• کیکِ بزرگ = keyk-e bozorg

In casual speech, you may hear something more like: barâye un jashn mikhâym ye keyk-e bozorg bekharim