Learn Hardcore Vietnamese: Tối nay tôi phải dọn bếp vì nó rất bẩn. - Tonight I have to clean the kitchen because it is very dirty.

Phải is a modal verb meaning “must / have to / need to (because of some obligation)”.
In tôi phải dọn bếp, it suggests you don’t really have a choice—you’re obliged to clean.

If you just say tối nay tôi dọn bếp, it’s more neutral: “I (will) clean the kitchen tonight” (a plan, but not explicitly an obligation).

How is the future shown here if there’s no word like “will”?

Vietnamese usually doesn’t mark tense with verb changes. Time is shown by:

Time expressions: tối nay = tonight (indicates future time)
Context

So tối nay tôi phải dọn bếp is understood as “I have to clean the kitchen tonight”, even though the verb dọn itself is not changed. You can add sẽ (future marker) — tối nay tôi sẽ phải dọn bếp — but it’s not necessary in everyday speech.

Can tối nay go somewhere else in the sentence?

Yes. Common options:

Tối nay tôi phải dọn bếp vì nó rất bẩn. (most natural)
Tôi tối nay phải dọn bếp vì nó rất bẩn. (possible, but less common)
Tôi phải dọn bếp tối nay vì nó rất bẩn. (also natural)
Placing tối nay at the beginning is very typical: it sets the time frame first, like “Tonight, I have to…”.

What’s the nuance difference between tối nay and đêm nay?

Both can translate as “tonight”, but:

tối nay: the evening and early night (more common in everyday speech)
đêm nay: the late night, or “tonight” with a slightly more dramatic/serious or poetic tone

For cleaning the kitchen, tối nay is the natural choice. Đêm nay would sound like you’re emphasizing the late-night timing or being a bit dramatic.

What does dọn mean exactly, and how is dọn bếp different from other “clean” verbs?

Dọn means to tidy up / clean up / clear up—often involving putting things in order, clearing surfaces, maybe wiping, etc.

Some related verbs:

lau: to wipe, mop (e.g. lau bàn, lau nhà)
rửa: to wash with water (e.g. rửa bát, rửa tay)
quét: to sweep (e.g. quét nhà)

Dọn bếp means to generally clean/tidy the kitchen (put dishes away, wipe counters, throw out trash…), not just one specific action like washing dishes.

Why is it just bếp and not cái bếp or nhà bếp?

bếp can mean the kitchen (as a place) or the stove, depending on context.
nhà bếp specifically means the kitchen (the room).
cái bếp usually means the stove / cooker (a specific item, with classifier cái).

In dọn bếp and nó rất bẩn here, bếp is understood as “the kitchen area” in general, not a single object, so no classifier is needed.

Is it natural to refer to bếp as nó? I thought nó was for animals or kids.

Nó is a third-person pronoun used for:

animals
things/objects
(informally) children or people you’re talking down to / about

Here nó refers back to bếp (the kitchen), which is an inanimate thing, so using nó is natural: vì nó rất bẩn = because it is very dirty.

You could also repeat the noun: vì bếp rất bẩn, which is a bit more neutral/formal.

What does rất add here? Could I say just bẩn?

Rất means “very”.

nó bẩn = it’s dirty
nó rất bẩn = it’s very dirty

Leaving rất out is grammatically fine; you just lose the emphasis. The original sentence is stressing how dirty it is, which helps explain why you have to clean.

Can I say rất là bẩn instead of rất bẩn?

Yes, rất là bẩn is possible in spoken Vietnamese, and many people say it.

However:

rất bẩn is a bit more standard/formal.
rất là bẩn can sound slightly more colloquial/emphatic in many dialects.

For learners, it’s safer to default to rất + adjective (here: rất bẩn).

Could I use vì differently or swap the clauses around?

Yes. The basic pattern is:

[reason] + nên + [result]
[result] + vì + [reason]

Your sentence is [result] + vì + [reason]:

Tối nay tôi phải dọn bếp vì nó rất bẩn.

You could also say:

Nó rất bẩn nên tối nay tôi phải dọn bếp.
(It’s very dirty, so tonight I have to clean the kitchen.)

Both are natural; vì focuses on “because”, nên focuses on “so/therefore.”

Could I drop tôi and just say Tối nay phải dọn bếp vì nó rất bẩn?

Yes, in casual conversation you can drop the subject pronoun if it’s obvious from context:

Tối nay phải dọn bếp vì nó rất bẩn.
→ understood as “(I/we) have to clean the kitchen tonight because it’s very dirty.”

Vietnamese often omits subjects when they are clear from context. However, for learners, it’s good practice to keep tôi until you’re comfortable with when dropping it is safe.

Is tôi always the right pronoun here, or would people use something else?

Tôi is a neutral, safe “I” in most situations, especially in writing or formal speech. In real-life conversation, Vietnamese speakers often use relationship-based pronouns instead, for example:

to someone older (if you’re male): con / em / cháu → Tối nay em phải dọn bếp…
between friends: could be mình, tao, etc., depending on closeness and region

The rest of the sentence stays the same; only the pronoun tôi changes with social context.