Вчера я купила маленькую сумочку для театра.

In the past tense, Russian verbs in the singular agree with the subject’s gender.

• я купил = I bought (said by a man)
• я купила = I bought (said by a woman)

So this sentence suggests the speaker is female.

Купила is perfective past tense, from купить. It presents the action as completed: the purchase happened and is finished.

That fits well with вчера (yesterday) when you are talking about one completed event.

Compare:

• Вчера я купила сумочку. = Yesterday I bought a handbag.
• Вчера я покупала сумочку. = Yesterday I was buying / was in the process of buying a handbag, or it may focus on the activity rather than the completed result.

So купила is the natural choice here.

Because маленькую сумочку is the direct object of the verb купила, it goes in the accusative case.

The noun is feminine singular:

• nominative: сумочка
• accusative: сумочку

The adjective has to agree with the noun in gender, number, and case:

• nominative: маленькая
• accusative: маленькую

So:

• маленькая сумочка = a small handbag (subject form)
• купила маленькую сумочку = bought a small handbag (object form)

Сумка is the general word for bag.

Сумочка is a diminutive form. It often suggests something like:

• a small bag
• a handbag / purse
• something a bit more cute, dainty, or elegant

So сумочка is often more natural than сумка if you mean a woman’s small handbag.

Not necessarily.

Even though сумочка is a diminutive, it often functions as a normal word for handbag/purse, not just literally little bag. So маленькую сумочку can simply mean:

• a small handbag
• a very small purse
• a dainty little bag

So the combination sounds natural.

Because the preposition для always requires the genitive case.

So:

• nominative: театр
• genitive: театра

That is why you get для театра.

This is a very common pattern:

• для мамы = for mom
• для работы = for work
• для театра = for the theater / for going to the theater

In this sentence, the most natural meaning is for going to the theater — in other words, a bag suitable for wearing to the theater.

So it means something like:

• a handbag for the theater
• a handbag to use when going to the theater
• possibly an evening bag

A literal gift for a theater building or institution would usually need more context.

Because в театр means to the theater or into the theater, usually expressing direction.

Examples:

• Я пошла в театр. = I went to the theater.
• Я взяла сумочку в театр. = I took a handbag to the theater.

But in your sentence, the idea is not movement. It is purpose/use: the bag is intended for theater-going. That is why для театра is used.

Yes, Russian word order is flexible.

Вчера is placed first to set the time frame right away: Yesterday...

You could also say:

• Я вчера купила маленькую сумочку для театра.

That is also correct.

Putting вчера first is very natural and often slightly more scene-setting or topic-setting. Russian word order often changes according to emphasis and information flow, not because of strict grammatical rules like in English.

Sometimes, yes — but only if the subject is already clear from context.

Russian often drops subject pronouns when they are understood. However, in the past tense, купила only tells you:

• singular
• feminine

It does not by itself tell you whether the subject is I or she.

So:

• Купила маленькую сумочку. could mean I bought a small handbag or She bought a small handbag, depending on context.

That is why я is helpful here.

Russian has no articles.

So маленькую сумочку can mean:

• a small handbag
• the small handbag

The exact meaning depends on context.

English forces you to choose a or the, but Russian does not. Learners often have to get used to letting context do that job.

The stress is:

Вчерá я купи́ла ма́ленькую су́мочку для теа́тра.

A rough pronunciation guide:

vchee-RA ya koo-PEE-la MA-len'koo-yoo SOO-mach-koo dlya tee-A-tra

A few useful notes:

• я is pronounced like ya
• для is roughly dlya
• unstressed vowels are reduced in real speech, so some sounds are less clear than spelling suggests

If you want to sound natural, getting the stress right is especially important:

• вчерá
• купи́ла
• ма́ленькую
• су́мочку
• теа́тра