वह आदमी हिंदी में सवाल लिख रहा है, और मैं अंग्रेज़ी में जवाब लिख रही हूँ।

वह can mean he, she, or that, depending on context.

When it comes before a noun, as in वह आदमी, it usually works like that:

• वह आदमी = that man

In context, English might translate it more naturally as the man or even just he, but the literal structure is that man.

Because वह आदमी is a full noun phrase: that man.

Compare:

• वह लिख रहा है = He is writing
• वह आदमी लिख रहा है = That man is writing

So आदमी is not extra or redundant. It specifies who वह refers to.

This is the Hindi present progressive (the be + -ing idea).

It is built like this:

• लिख = write
• रहा / रही / रहे = progressive part
• है / हूँ / हैं = form of to be

So:

• लिख रहा है = is writing
• लिख रही हूँ = am writing

A very common pattern in Hindi is:

verb stem + रहा/रही/रहे + form of होना

Because रहा / रही / रहे agrees with the subject's gender and number.

In this sentence:

• वह आदमी ... लिख रहा है → आदमी is masculine singular, so रहा
• मैं ... लिख रही हूँ → the speaker is female, so रही

If the speaker were male, it would be:

• मैं अंग्रेज़ी में जवाब लिख रहा हूँ।

These are different present-tense forms of होना (to be).

• है = is / used with he, she, it, that person
• हूँ = am / used with I

So:

• वह आदमी ... लिख रहा है = That man is writing
• मैं ... लिख रही हूँ = I am writing

में is a postposition meaning in.

So:

• हिंदी में = in Hindi
• अंग्रेज़ी में = in English

Hindi uses postpositions, which come after the noun, unlike English prepositions, which come before it.

So Hindi says:

• Hindi in rather than
• in Hindi

Hindi usually prefers Subject–Object–Verb order, and other phrases often come before the verb too.

So this is a very natural order:

• वह आदमी हिंदी में सवाल लिख रहा है
  • subject: वह आदमी
  • language phrase: हिंदी में
  • object: सवाल
  • verb: लिख रहा है

Some reordering is possible in Hindi for emphasis, but this version is normal and clear.

In this form, they can be singular or plural, depending on context.

Here they are naturally understood as questions and answers, but the word form itself does not change.

That is because many masculine nouns ending in a consonant, like सवाल and जवाब, have the same form in the direct singular and direct plural.

So:

• सवाल can mean a question or questions
• जवाब can mean an answer or answers

Context tells you which meaning is intended.

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

So Hindi often leaves that idea to context.

For example:

• आदमी can mean a man, the man, or just man
• वह आदमी often gives a more specific sense, like that man or the man

This is very normal in Hindi, and learners usually get used to it quickly.

Yes, often it could.

Hindi frequently drops subject pronouns when the meaning is clear from context and the verb form.

So you could say:

• अंग्रेज़ी में जवाब लिख रही हूँ।

That still clearly means I am writing answers in English, especially because हूँ shows first person.

But in your sentence, मैं is useful because it creates a clear contrast:

• that man ...
• and I ...

It is pronounced roughly like hoon, but with a nasalized long oo sound.

A simple learner-friendly approximation is:

• hū̃

The mark above the letter shows nasalization. In everyday speech, many learners hear it as something close to hoon, which is a good starting point.

Only the gender-marked part would change:

• female speaker: मैं ... लिख रही हूँ
• male speaker: मैं ... लिख रहा हूँ

So the full sentence would become:

वह आदमी हिंदी में सवाल लिख रहा है, और मैं अंग्रेज़ी में जवाब लिख रहा हूँ।

The same idea applies to other subjects too: the रहा / रही / रहे part changes to match gender and number.