Cậu muốn ở đây mãi.

Cậu is a Vietnamese pronoun meaning you in this sentence.

It is not a neutral, all-purpose you like in English. Vietnamese pronouns depend a lot on relationship, age, and social context. Cậu is commonly used:

• for a friend of similar age
• for someone younger in some contexts
• in certain family or regional usages with different meanings

So Cậu muốn ở đây mãi sounds like you are speaking somewhat casually and personally to someone, not in a very formal situation.

If you were speaking more politely, you might use a different pronoun, such as:

• bạn
• anh
• chị
• em

depending on who the person is.

It is capitalized simply because it is the first word of the sentence.

Vietnamese capitalizes the first word of a sentence just like English does. So Cậu here is just the normal word cậu, written with a capital C because it comes first.

Muốn means to want.

In this sentence, it expresses desire or intention:

• cậu muốn = you want

It is followed directly by what the person wants to do:

• ở đây = stay/be here

So the structure is basically:

• cậu muốn ở đây mãi
• you want to stay here forever

Vietnamese does not need a separate word for to before the verb the way English often does.

Because Vietnamese does not use to in the same way English does in verb combinations.

In English, we say:

• want to stay

In Vietnamese, you usually just put the second verb after muốn:

• muốn ở

So:

• muốn ở đây literally looks like want stay here

This is a very normal Vietnamese pattern.

Ở can mean be/stay/live depending on context.

In this sentence, ở đây mãi most naturally means:

• stay here forever or
• be here forever

In other contexts, ở can also mean:

• live at/in
  • Tôi ở Hà Nội = I live in Hanoi

So ở is a flexible word, and context tells you whether it is closer to be, stay, or live.

Đây means here.

So:

• ở đây = be/stay here

Vietnamese often uses short location words like:

• đây = here
• đó / đấy = there
• kia = over there

Mãi here means something like:

• forever
• for a long time
• indefinitely
• continuously, depending on context

In ở đây mãi, it gives the idea of staying here without end, or for a very long time. So the natural English meaning is usually:

• stay here forever

It often adds a sense of duration that continues on and on.

Not always.

Mãi often suggests something lasting a very long time, sometimes permanently, but the exact English translation depends on context. It can mean:

• forever
• always
• endlessly
• for a long time

For example:

• chờ mãi = wait and wait / wait for a very long time
• nhớ mãi = remember forever / never forget

So in this sentence, forever is a very natural translation, but mãi is a little broader than just one fixed English word.

Vietnamese word order here is very straightforward:

• cậu = subject
• muốn = want
• ở đây = stay/be here
• mãi = forever / continuously

So the sentence follows a pattern like:

• Subject + want + verb phrase + time/duration word

In other words:

• You + want + stay here + forever

This is normal Vietnamese word order.

Sometimes adverbs in Vietnamese can move around a little depending on style and emphasis, but ở đây mãi is a very natural order.

For this sentence, Cậu muốn mãi ở đây would sound less natural in most everyday contexts. The most common phrasing is:

• Cậu muốn ở đây mãi

So as a learner, it is best to remember mãi after the place/action phrase here.

Yes, it is grammatical and understandable.

It sounds like:

• You want to stay here forever or
• You want to be here forever

Depending on context, native speakers might also say:

• Cậu muốn ở đây mãi à? = You want to stay here forever?
• Cậu muốn ở đây mãi sao? = You want to stay here forever?

Those versions sound more clearly conversational if you are asking someone.

But the basic sentence Cậu muốn ở đây mãi is natural as a statement.

Vietnamese often makes questions by keeping the same word order and adding a question particle or question intonation.

For example:

• Cậu muốn ở đây mãi à?
• Cậu muốn ở đây mãi sao?

Both can mean:

• Do you want to stay here forever?

You can also sometimes rely just on intonation in speech, but particles like à and sao make the question clearer.

Yes, in the right context, Vietnamese often drops pronouns when they are already understood.

So:

• Muốn ở đây mãi could mean:
• (You) want to stay here forever
• (I) want to stay here forever
• or another subject, depending on context

Vietnamese is very context-dependent. If it is already obvious who is being talked about, the pronoun can be omitted.

But if you want to be clear, especially as a learner, keeping cậu is helpful.

No tense is marked explicitly here.

Vietnamese does not inflect verbs for tense the way English does. Muốn and ở do not change form. The time reference comes from context or from extra time words.

So Cậu muốn ở đây mãi could be understood as:

• You want to stay here forever
• You want to be here forever

If needed, Vietnamese can add time markers, for example:

• Bây giờ cậu muốn ở đây mãi = Right now you want to stay here forever
• Sau này cậu muốn ở đây mãi = Later/in the future you want to stay here forever

A rough guide is:

• Cậu: sounds a bit like guh-u with a dipping tone
• muốn: roughly moo-uhn with a rising-broken tone
• ở: like a short uh with a questioning/rising quality
• đây: roughly like day
• mãi: roughly my with a rising-broken tone

A more important point than English-style approximation is the tones:

• cậu has a nặng tone
• muốn has a sắc tone
• ở has a hỏi tone
• đây has a ngang tone
• mãi has a ngã tone

Exact pronunciation varies somewhat by dialect, especially between northern and southern Vietnamese.

It can sound affectionate, emotional, or reflective depending on context.

For example, it could suggest:

• attachment to a place
• reluctance to leave
• comfort and happiness
• even a romantic or sentimental mood

Because of mãi, the sentence feels stronger than just:

• Cậu muốn ở đây = You want to stay here

Adding mãi makes it feel more lasting and emotionally charged:

• You want to stay here forever

Yes, often you can, but the tone changes a little.

• Cậu muốn ở đây mãi sounds more personal/casual in many contexts.
• Bạn muốn ở đây mãi is often more neutral and broadly usable for you among peers.

Both can be correct, but Vietnamese pronouns are very context-sensitive. Native speakers choose them based on age, closeness, and social relationship.

As a learner, bạn is often safer than cậu if you are unsure, though it is still not perfect for every situation.

It is complete on its own.

Vietnamese sentences can be quite short and still feel complete. This one has:

• a subject: cậu
• a main verb: muốn
• a following verb phrase: ở đây
• a duration/intensity word: mãi

So it is a full, natural sentence, not a fragment.