Tôi rất mệt, vì vậy tôi muốn nghỉ ở nhà.

Vietnamese often does not use a verb like to be when describing a state or quality.

So:

• Tôi rất mệt = I am very tired
• literally, it is closer to I very tired

This is normal Vietnamese sentence structure. Adjectives like mệt can act directly as the predicate.

Rất means very.

In Vietnamese, degree words like rất usually come before the adjective:

• rất mệt = very tired
• rất vui = very happy
• rất bận = very busy

So the order is:

• rất + adjective

not the English-style pattern of adjective first.

Mệt means tired or fatigued.

Mệt mỏi also means tired, but it can sound a little fuller or more emphatic, like exhausted / weary / worn out, depending on context.

Examples:

• Tôi mệt. = I’m tired.
• Tôi rất mệt. = I’m very tired.
• Tôi mệt mỏi. = I feel tired / worn out.

In everyday speech, mệt is very common and natural.

Yes, you often can leave it out if the subject is already clear.

So both of these are natural:

• Tôi rất mệt, vì vậy tôi muốn nghỉ ở nhà.
• Tôi rất mệt, vì vậy muốn nghỉ ở nhà.

Repeating tôi makes the sentence a little clearer and more complete, especially for learners or in careful speech. Vietnamese often omits repeated subjects when the meaning is obvious from context.

Vì vậy means therefore, so, or for that reason.

It connects the first clause to the result in the second clause:

• Tôi rất mệt = cause
• vì vậy tôi muốn nghỉ ở nhà = result

So the structure is:

• cause, vì vậy result

It is a little more formal or explicit than just saying nên.

Yes. In many everyday situations, nên sounds more natural and more common.

For example:

• Tôi rất mệt, nên tôi muốn nghỉ ở nhà.

This also means I’m very tired, so I want to rest at home.

A rough comparison:

• vì vậy = therefore / for that reason
• nên = so

Both are correct here.

Not in the same way.

• vì and bởi vì mean because
• vì vậy means therefore / so

So:

• Tôi muốn nghỉ ở nhà vì tôi rất mệt. = I want to stay home because I’m very tired.
• Tôi rất mệt, vì vậy tôi muốn nghỉ ở nhà. = I’m very tired, so I want to stay home.

These say almost the same thing, but the sentence structure is different.

In Vietnamese, after muốn (want), you usually put the next verb directly.

So:

• muốn nghỉ = want to rest
• muốn ăn = want to eat
• muốn đi = want to go

Vietnamese does not need an extra word like English to here.

Pattern:

• muốn + verb

Here, nghỉ means rest, take a break, or stay off from normal activity.

Depending on context, nghỉ can mean:

• to rest
• to take a break
• to be off work/school
• to stop for a while

In this sentence, it most naturally means something like:

• rest
• take it easy
• stay home and rest

If you want to emphasize the physical act of resting, you might also hear nghỉ ngơi.

Both can mean rest, but there is a slight difference.

• nghỉ is shorter and more flexible
• nghỉ ngơi more clearly emphasizes resting/relaxing

So:

• Tôi muốn nghỉ ở nhà. = natural, everyday
• Tôi muốn nghỉ ngơi ở nhà. = I want to rest/relax at home

Both are correct. Nghỉ ở nhà is fine, but nghỉ ngơi ở nhà can sound a little more explicitly restful.

Because ở nhà tells you where the action happens: at home.

In Vietnamese, location phrases often come after the verb:

• nghỉ ở nhà = rest at home
• ăn ở nhà = eat at home
• học ở trường = study at school

So the order is very often:

• verb + location

Ở means at / in / staying at, and nhà means house / home.

Together:

• ở nhà = at home

In many contexts, nhà is best translated as home, not just house.

It is not always absolutely required in casual writing, but it is very normal and helpful.

The comma separates:

1. the reason: Tôi rất mệt
2. the result: vì vậy tôi muốn nghỉ ở nhà

So the comma makes the sentence easier to read. In careful writing, it is a good choice.

Yes, it is natural and correct.

That said, in everyday speech, many people might say one of these:

• Tôi rất mệt, nên tôi muốn nghỉ ở nhà.
• Tôi mệt quá, nên muốn ở nhà nghỉ.
• Tôi rất mệt, nên muốn nghỉ ngơi ở nhà.

Your original sentence is clear and good. It may sound slightly more careful or formal because of vì vậy.

A few words here can be difficult for English speakers:

• tôi: the ôi sound is important
• rất: short vowel, and the final t is unreleased
• mệt: also ends in an unreleased t
• nghỉ: the ngh beginning and the tone can be hard
• ở: short but important tone
• nhà: easy to hear in common speech, but keep the falling tone

Two especially important points:

1. Final t in words like rất and mệt is not strongly released like in English.
2. Tones matter a lot. Saying the wrong tone can make the word unclear or sound like another word.

If you want, I can also break the whole sentence down word by word for pronunciation.