من در کلاس کم صحبت میکنم، چون خسته ام.

Yes. In Persian, the verb ending -م in می‌کنم already tells you the subject is I.

So من is often optional here:

• من در کلاس کم صحبت می‌کنم
• در کلاس کم صحبت می‌کنم

Both are grammatical. Including من can add a little emphasis, clarity, or contrast.

در کلاس means in class / in the classroom.

• در = in
• کلاس = class

A learner should know that در is correct, but in everyday spoken Persian people often say تو کلاس instead of در کلاس.

So:

• در کلاس = a bit more neutral/written/formal
• تو کلاس = very common in speech

In Persian, adverbs like کم usually come before the verb or verbal expression they modify.

So:

• کم صحبت می‌کنم = I speak little / I don’t speak much

This is the normal order. Persian often puts important information right before the verb.

A few useful comparisons:

• کم می‌خورم = I eat little
• زیاد حرف می‌زند = he/she talks a lot
• آهسته راه می‌روم = I walk slowly

It functions like a verb, but it is actually a compound verb.

It is made of:

• صحبت = speech, conversation
• کردن / می‌کنم = to do / I do

So صحبت کردن literally looks like to do conversation, but it simply means to speak / to talk.

Persian uses many compound verbs like this:

• کار کردن = to work
• فکر کردن = to think
• استفاده کردن = to use

In this sentence, می‌کنم is the present form of کردن used in a habitual or general sense.

It breaks down like this:

• می- = present/imperfective marker
• کن = present stem of کردن
• -م = I

So می‌کنم means I do, I am doing, or in many contexts I usually do, depending on the sentence.

In صحبت می‌کنم, it gives the meaning I speak / I talk.

Persian often uses short attached forms of to be after adjectives and nouns.

So:

• خسته‌ام = I am tired
• خسته‌ای = you are tired
• خسته است = he/she is tired

The -ام is the I am part.

Using هستم is possible:

• خسته هستم

But خسته‌ام is usually more natural and common.

The most standard spelling is خسته‌ام with a half-space (also called a zero-width non-joiner).

So you may see:

• خسته‌ام → standard written form
• خسته ام → very common in casual typing
• خستم → more colloquial/spoken-style writing

Similarly, standard spelling is:

• می‌کنم not
• میکنم

In casual text, many people skip the half-space, but learners should recognize the standard forms.

چون means because.

It introduces the reason:

• first clause: در کلاس کم صحبت می‌کنم
• reason clause: چون خسته‌ام

So Persian works very similarly to English here.

You can also put the reason first:

• چون خسته‌ام، در کلاس کم صحبت می‌کنم.

That is also correct.

Yes, absolutely.

A very natural version is:

• در کلاس کم صحبت می‌کنم، چون خسته‌ام.

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

You usually keep من when:

• you want emphasis
• you are contrasting with someone else
• you want extra clarity

For example:

• من کم صحبت می‌کنم، ولی دوستم زیاد صحبت می‌کند.

It is correct and natural, but Persian has other common ways to express the same idea.

For example:

• کم حرف می‌زنم = I don’t talk much
• زیاد صحبت نمی‌کنم = I don’t speak much
• تو کلاس ساکتم = I’m quiet in class

The original sentence is completely fine.
A slightly more everyday spoken version might be:

• تو کلاس کم حرف می‌زنم، چون خسته‌م.

A rough pronunciation is:

man dar kelâs kam sohbat mikonam, چون khaste-am

A few notes:

• کلاس sounds like kelâs
• صحبت is commonly pronounced close to sohbat
• می‌کنم is pronounced mikonam
• خسته‌ام is often said quickly as khaste-am or even more smoothly in speech

In casual spoken Persian, it may sound a bit more like:

• man tu kelâs kam harf mizanam, چون khastam

That is not a word-for-word rewrite of the original, just a common spoken-style alternative.