मैं दोस्त को बुलाऊँगी, फिर हम बातें करेंगे।

Because the speaker is female.

In Hindi, future-tense verbs often agree with the gender and number of the subject.

• मैं बुलाऊँगी = I will call (said by a woman)
• मैं बुलाऊँगा = I will call (said by a man)

So बुलाऊँगी tells you that मैं refers to a female speaker.

It comes from the verb बुलाना = to call / to invite / to summon.

A simple way to think of it is:

• verb stem: बुला-
• future ending for मैं (female): -ऊँगी

So:

• बुला + ऊँगी = बुलाऊँगी

Related forms:

• मैं बुलाऊँगा = I will call (male speaker)
• तुम बुलाओगे / बुलाओगी = you will call
• वह बुलाएगा / बुलाएगी = he/she will call

को marks the object, especially when it is a person, an animate being, or a specific individual.

So in:

• दोस्त को बुलाऊँगी

the friend is the person being called.

With people, को is very common and often expected.

Compare:

• मैं दोस्त को बुलाऊँगी = I will call the friend / my friend
• मैं किताब पढ़ूँगी = I will read a book/the book

You usually do not use को with an ordinary non-human direct object like किताब, unless there is some special context.

Because the subject changes.

In the first clause:

• मैं दोस्त को बुलाऊँगी = I will call the friend

In the second clause:

• फिर हम बातें करेंगे = then we will talk

After the friend arrives or is contacted, the action is no longer just done by I; it is done by we.

That is why Hindi uses:

• हम = we
• करेंगे = will do

If the sentence said मैं बातें करूँगी, it would mean I will talk, not we will talk.

Because करेंगे agrees with हम = we, not just with the speaker alone.

In standard Hindi, हम normally takes plural verb forms:

• हम करेंगे = we will do
• हम जाएँगे = we will go
• हम बोलेंगे = we will speak

Even if the group is all female, standard textbook Hindi very often still uses the plural form -ेंगे with हम.

So here, करेंगे is the normal future plural form with हम.

बातें करना is a very common Hindi expression meaning to talk / to chat / to have a conversation.

Literally:

• बात = a matter, thing said, topic
• बातें = matters / बातें (plural)
• बातें करना = to do talking / to chat

Hindi often uses a noun + करना structure where English would just use a simple verb.

So:

• हम बातें करेंगे = we will talk / we will chat

The plural बातें sounds natural here because conversation usually involves multiple things being said, not just one single बात.

Hindi usually follows Subject–Object–Verb order, while English usually prefers Subject–Verb–Object.

So Hindi says:

• मैं दोस्त को बुलाऊँगी
• literally: I friend to will-call

Where English says:

• I will call the friend

The main verb often comes at the end of the clause in Hindi.

The second part works the same way:

• हम बातें करेंगे
• literally: we talk will-do

So the sentence is normal Hindi word order.

Hindi does not have articles like English a, an, and the.

So दोस्त can mean:

• friend
• a friend
• the friend
• my friend

Which one is intended depends on context.

In this sentence, दोस्त को most naturally means something like:

• the friend
• my friend
• a particular friend

because को often makes the object sound more specific.

Not necessarily.

दोस्त is commonly used for friend in a fairly general way and can refer to a male or female friend, depending on context.

So from this sentence alone, you cannot be fully sure about the friend’s gender.

If someone wanted to make it clearer, they might use other words in context, but दोस्त itself is often left general in everyday Hindi.

फिर means then / after that / next, and it is fairly flexible in position.

In this sentence:

• मैं दोस्त को बुलाऊँगी, फिर हम बातें करेंगे।

it naturally links the two actions: first calling the friend, then talking.

You may also hear similar placement patterns like:

• फिर हम बातें करेंगे
• हम फिर बातें करेंगे

But the exact nuance can shift a little depending on emphasis. In your sentence, the position is very natural and clear for sequencing events.

Sometimes yes, because Hindi often allows subjects to be dropped when they are clear from context.

For example:

• दोस्त को बुलाऊँगी can still mean I will call the friend
• फिर बातें करेंगे can sometimes mean then we’ll talk

However, keeping मैं and हम makes the sentence clearer, especially for learners and in situations where the subject might otherwise be ambiguous.

So the full sentence:

• मैं दोस्त को बुलाऊँगी, फिर हम बातें करेंगे।

is completely natural and very clear.

Both words contain nasalization, shown in writing by ँ.

• मैं is pronounced roughly like main with a nasalized vowel
• बुलाऊँगी is roughly bu-laa-oon-gee, with the ऊँ nasalized

A simple learner-friendly transliteration is:

• Main dost ko bulaaungi, phir ham baatein karenge.

You do not need to pronounce a full extra n sound every time; often it is more like the vowel itself becomes nasal.

That nasal quality is an important part of natural Hindi pronunciation.