Learn Hardcore Vietnamese: Hôm nay tôi mặc áo màu xanh và nó rất sạch. - Today I am wearing a green shirt and it is very clean.

Adjectives can function like verbs.
You normally do not add a verb like là before an adjective that describes a property of a thing/person:
- Cái áo này sạch. – This shirt is clean.
- Trời nóng. – It’s hot.

You only use là before nouns or noun phrases:

Anh ấy là bác sĩ. – He is a doctor.
Hôm nay là thứ hai. – Today is Monday.

How is tense shown? I don’t see any word that means “am wearing” or shows it’s present.

Vietnamese verbs do not change form to show tense (no conjugation), and often no extra word is used at all.

In Hôm nay tôi mặc áo màu xanh, the time word hôm nay (today) tells you it’s present.

tôi mặc can mean:
- I wear (habitually)
- I am wearing (right now)
- I wore (in the past), etc.,
  depending on context or added time words.

If you wanted to make the “right now / currently doing” idea extra clear, you could say:

Hôm nay tôi đang mặc áo màu xanh. – Today I am wearing a blue/green shirt.

Here đang marks an ongoing action, similar to English “am/are/is … -ing”.

What exactly does mặc mean, and when do I use it instead of other clothing verbs?

mặc means to wear / to put on clothing on the body, especially items like shirts, pants, dresses, jackets.

Common clothing verbs:

mặc – wear/put on clothing:
- mặc áo – wear/put on a shirt/top
- mặc quần – wear/put on pants
đội – wear/put on things on the head:
- đội mũ – wear/put on a hat
mang – wear/carry on feet or hands:
- mang giày – wear shoes
- mang dép – wear sandals
- mang găng tay – wear gloves
đeo – wear things that hang on the body:
- đeo kính – wear glasses
- đeo túi – carry/wear a bag
- đeo vòng cổ – wear a necklace

So for a shirt, mặc áo is the right verb.

What does áo mean by itself? Does it specifically mean “shirt”?

áo is a general word for a garment worn on the upper body – a top. In many contexts it is naturally understood as shirt, but it can be broader.

Examples:

áo sơ mi – a (button-up) shirt
áo phông / áo thun – a T‑shirt
áo khoác – a jacket
áo len – a sweater

In your sentence, áo on its own is most naturally understood as shirt/top. If context is clear, Vietnamese often doesn’t bother to specify more.

Why is there no word for “a” or “the” before áo?

Vietnamese has no articles like a/an or the. Whether English would use a or the is inferred from context or added details.

áo can mean:
- a shirt
- the shirt
- shirts (in general), depending on context.

If you really want to specify one shirt, you can add a number and a classifier:

một cái áo – one shirt / a shirt
cái áo này – this shirt
cái áo đó – that shirt

In your sentence, tôi mặc áo màu xanh is naturally understood as “I’m wearing a blue/green shirt” or “I’m wearing my blue/green shirt”, depending on context. Vietnamese doesn’t need to show that difference grammatically.

Is áo màu xanh different from áo xanh? Why add màu?

Both are correct, and both can mean a blue/green shirt.

áo xanh – literally “blue/green shirt”
áo màu xanh – literally “shirt [of] blue/green color”

Differences:

áo xanh is a bit shorter and very common in speech.
áo màu xanh can sound slightly more explicit that you are talking about the color; it can feel a little more descriptive or careful, but in everyday speech many people use them interchangeably.

You’ll hear both forms a lot:

tóc đen / tóc màu đen – black hair
xe đỏ / xe màu đỏ – red car

Does xanh mean “blue” or “green”? Which one is it here?

xanh by itself can mean blue or green, because historically they were seen as shades of the same basic color.

To be more specific, Vietnamese often adds a second word:

xanh lá (cây) – green (leaf‑green)
xanh lục – green (more technical/formal)
xanh dương – blue (sky‑blue)
xanh da trời – blue (sky color)
xanh biển – ocean blue

In áo màu xanh, without extra context, it just means a blue/green shirt. In real life, context (pointing, previous description, typical color of that item) often tells you if it’s blue or green.

Why is nó used for “it”? Can Vietnamese use nó for people too?

In this sentence, nó refers to the shirt and means it, which is fine because nó is commonly used for things and animals.

For objects / animals: nó is normal and neutral:
- Con mèo của tôi, nó rất dễ thương. – My cat, it is very cute.
- Cái áo này, nó rất sạch. – This shirt, it is very clean.
For people, nó often sounds impolite, rude, or dismissive, especially if the person is present or equal/higher status. It’s sometimes used about:
- children (in a scolding or rough way),
- people you look down on,
- or in very casual talk between close friends about a third person.

For people, you normally use:

anh ấy / chị ấy / cô ấy / ông ấy / bà ấy, etc.,
or a kinship/pronoun pair like anh, em, cô, chú, depending on age/relationship.

For an inanimate thing like áo, nó rất sạch is normal.

Could you drop nó and just say và rất sạch? Would that still be correct?

Yes, you can drop nó if the subject is very clear from context:

Hôm nay tôi mặc áo màu xanh, rất sạch.

This is acceptable in spoken Vietnamese and sometimes in writing. It reads like:

“Today I wear a blue/green shirt, (it’s) very clean.”

However:

In a textbook-style sentence, including nó makes the structure clearer for learners.
Omitting it can feel more informal or stylistic.

So both:

Hôm nay tôi mặc áo màu xanh và nó rất sạch.
Hôm nay tôi mặc áo màu xanh, rất sạch. are understandable. The first is more explicit and neutral.

What does rất do here? How strong is it, and where does it go?

rất is an adverb meaning very. It goes before the adjective:

rất sạch – very clean
rất đẹp – very beautiful
rất tốt – very good

Strength:

rất is a normal, neutral “very”, not too strong, not too weak.
Stronger options: cực kỳ sạch, vô cùng sạch, siêu sạch.
Milder or more colloquial: khá sạch (quite clean), sạch lắm (very clean, with lắm at the end).

Position:

rất + adjective:
- nó rất sạch – it is very clean.

Why is tôi used here? Are there other common words for “I / me” in Vietnamese?

tôi is a neutral, relatively formal way to say I / me, good for:

talking to strangers,
formal or semi-formal situations,
when you’re not sure which pronoun is socially correct.

Vietnamese pronouns depend heavily on age, gender, and relationship. Common alternatives:

em – I (when you are younger than the listener, or in couple talk if you are the “younger” one)
anh – I (adult male, speaking to someone younger or to a girlfriend/wife)
chị – I (adult female, speaking to someone younger or to a boyfriend/husband)
con – I (speaking to parents, older relatives)
cháu – I (speaking to much older people, like grandparents’ age)

So in real situations, you might hear:

Hôm nay em mặc áo màu xanh…
Hôm nay anh mặc áo màu xanh…

But tôi is the safest “dictionary” pronoun and is fine in many contexts.

Could you leave out tôi and just say Hôm nay mặc áo màu xanh?

Yes, dropping the subject pronoun is possible when it’s clear from context.

Hôm nay mặc áo màu xanh. – (I) wear/am wearing a blue/green shirt today.

In conversation, if it’s obvious that you’re talking about yourself, people often omit tôi, em, etc. This sounds more casual.

However:

For learning and for clear, standalone sentences, it’s good practice to include the pronoun:
- Hôm nay tôi mặc áo màu xanh.

Can và be omitted? Could I just have two short sentences instead of one joined with và?

Yes, both structures are possible:

Single sentence with và:
- Hôm nay tôi mặc áo màu xanh và nó rất sạch.
  → Today I’m wearing a blue/green shirt and it is very clean.
Two separate sentences:
- Hôm nay tôi mặc áo màu xanh. Nó rất sạch.
  → Today I’m wearing a blue/green shirt. It is very clean.
Comma plus descriptive tail (more informal/written style):
- Hôm nay tôi mặc áo màu xanh, rất sạch.

All three are grammatical. Using và simply makes the connection between the two ideas explicit, like “and” in English.