او همیشه سریع به سوال من جواب میدهد، اما امروز خیلی خسته است.

Yes. او can mean he or she. Persian does not normally mark gender in third-person singular pronouns, so the same word is used for both.

A learner often has to figure out the gender from:

• context
• previous sentences
• real-world knowledge

In everyday speech, او is a bit more formal than اون, which is very common in conversation.

همیشه means always, and it is functioning as an adverb of frequency.

In Persian, adverbs like همیشه, امروز, خیلی, and سریع are often fairly flexible in position, but they usually appear before the part they modify, or somewhere before the verb.

So in this sentence:

• او همیشه سریع به سوال من جواب میدهد
• literally something like: He/She always quickly to my question answers

Persian is generally SOV:

• Subject: او
• Object/complement: به سوال من
• Verb: جواب میدهد

The adverbs come before the final verb.

Here, به means something like to.

The expression جواب دادن literally means to give an answer, and the thing or person receiving the answer is commonly introduced with به.

So:

• به سوال من جواب میدهد = he/she answers my question
• more literally: he/she gives an answer to my question

This is very natural Persian usage.

Persian often uses a noun + light verb combination, and this is one of the most common patterns in the language.

Here:

• جواب = answer
• دادن = to give

So جواب دادن literally means to give an answer, but in natural English it is simply to answer.

A learner should get used to these combinations, because Persian uses them a lot. Similar patterns include:

• سوال کردن = to ask a question
• تصمیم گرفتن = to make a decision
• کمک کردن = to help

میدهد is the present habitual/simple form of دادن in third-person singular.

It breaks down like this:

• میـ = present/imperfective marker
• ده = present stem of دادن
• ـد = third-person singular ending

So:

• می‌دهد / میدهد = he/she gives, he/she answers

In careful modern spelling, you will often see it written as می‌دهد.
Writing it as میدهد is also common in less formal typing.

In Persian, many words can function as adjectives and adverbs without changing form.

So سریع can mean:

• fast / quick as an adjective
• quickly as an adverb

Here it modifies the verb phrase, so it means quickly.

This is very common in Persian. Unlike English, Persian often does not add a special ending like -ly.

Yes, that would also be understandable and natural.

Persian has some flexibility with adverb placement, especially with words like سریع. Both of these are possible:

• او همیشه سریع به سوال من جواب میدهد
• او همیشه به سوال من سریع جواب میدهد

The first one may feel slightly smoother to many speakers, but both work. The verb still comes at the end.

Because Persian usually puts the possessor after the noun.

So:

• سوال من = my question
• literally: question of me

This is the normal Persian pattern:

• کتاب من = my book
• دوست من = my friend
• خانه ما = our house

English puts the possessor first; Persian usually puts it after the noun.

In Persian, adjectives are often used with the verb to be.

So:

• خسته = tired
• است = is

Together:

• خسته است = is tired

And:

• خیلی خسته است = is very tired

This is directly parallel to English in meaning, even though Persian places the verb at the end.

خیلی means very here.

It modifies the adjective خسته:

• خسته = tired
• خیلی خسته = very tired

In other contexts, خیلی can also mean a lot, depending on what it modifies.

Examples:

• خیلی خوب = very good
• خیلی کار می‌کند = he/she works a lot

Yes. اما is a common word meaning but.

It is slightly more formal or neutral than some spoken alternatives. In conversation, learners will also hear:

• ولی
• اما
• sometimes ولی خب in casual speech

In your sentence, اما is perfectly natural and clear.

امروز means today, and Persian allows time expressions to appear in different places.

So all of these can work, depending on emphasis:

• او همیشه سریع به سوال من جواب میدهد، اما امروز خیلی خسته است.
• امروز او خیلی خسته است.
• او امروز خیلی خسته است.

In your sentence, امروز contrasts nicely with همیشه:

• usually he/she answers quickly
• but today he/she is very tired

So its position helps express that contrast.

It is mostly standard written Persian, but still very natural.

A few notes:

• او is more formal than everyday spoken اون
• است is standard; in speech it may sound shorter
• می‌دهد is the standard written form
• in casual speech, people may say something closer to جواب می‌ده instead of جواب می‌دهد

A more conversational version might be:

• اون همیشه سریع به سوال من جواب می‌ده، اما امروز خیلی خسته‌ست.

But the sentence you were given is perfectly normal and useful to learn.

No. Another common word is پاسخ.

So you may also see:

• به سوال من پاسخ می‌دهد

That is usually a bit more formal or literary than جواب می‌دهد.

In everyday Persian, جواب دادن is extremely common and very useful, so it is a great pattern to learn first.