Nước hôm qua không hề thấm vào tường.

In Vietnamese, time expressions are flexible. Hôm qua can appear:

• near the beginning: Hôm qua, nước không hề thấm vào tường.
• after the subject: Nước hôm qua không hề thấm vào tường.

In this sentence, nước hôm qua is most naturally understood as the water from yesterday or yesterday’s water, not just water ... yesterday.

So the placement suggests that hôm qua is closely connected to nước. It narrows down which water we are talking about.

It most likely means yesterday’s water or the water from yesterday.

Vietnamese often places a time expression after a noun to identify it:

• cuộc họp hôm qua = yesterday’s meeting
• bài báo hôm nay = today’s article
• nước hôm qua = yesterday’s water

If the speaker only wanted to say Yesterday, the water..., they would more commonly say:

• Hôm qua, nước không hề thấm vào tường.

So in your sentence, hôm qua is probably modifying nước, not the whole clause.

Vietnamese does not have articles like the or a/an.

Whether something is definite or indefinite is usually understood from context. So:

• nước can mean water, the water, or some water
• tường can mean wall, the wall, or a wall

In this sentence, English naturally uses the wall because the wall is probably known from context, but Vietnamese does not need a separate word for that.

Because hôm qua already shows past time clearly.

Vietnamese often does not need a separate past marker when a time expression makes the time obvious:

• Hôm qua tôi đi học. = I went to school yesterday.
• Nước hôm qua không hề thấm vào tường.

You could add đã in some contexts, but it is not necessary here. The sentence is perfectly natural without it.

Không hề is stronger than plain không.

• không = not / did not
• không hề = not at all / never did / absolutely did not

So:

• không thấm vào tường = did not seep into the wall
• không hề thấm vào tường = did not seep into the wall at all

It adds emphasis and makes the negation stronger.

Here, thấm means to seep, to soak through, or to penetrate by absorption.

It is used for liquids going into a material, for example:

• Nước thấm vào đất. = Water seeps into the soil.
• Mưa thấm qua áo. = Rain soaks through the shirt.
• Nước thấm vào tường. = Water seeps into the wall.

So it is not just ordinary movement like go into. It specifically suggests liquid being absorbed or penetrating gradually.

Vào means into, and it shows the direction or target of the seepage.

• thấm = seep / soak in
• thấm vào = seep into

So:

• thấm vào tường = seep into the wall

In many Vietnamese verb phrases, a main verb is followed by another word showing direction or result. Here vào makes the destination explicit.

Sometimes yes, but the meaning may feel less complete or slightly different.

• Nước không hề thấm vào tường. = Water did not seep into the wall at all.
• Nước không hề thấm tường. = possible in some contexts, but less standard/common for many learners’ purposes

Using vào is the safest and clearest way to express into the wall.

Both are possible, but they are used differently.

• tường = wall
• bức tường = a wall / the wall, with a classifier-like noun bức often used for flat vertical structures

In everyday Vietnamese, people often just say tường when the meaning is obvious:

• sơn tường = paint the wall
• dựa vào tường = lean against the wall
• nước thấm vào tường = water seeps into the wall

Using bức tường can sound a little more specific or descriptive, but tường alone is very normal.

By itself, nước just means water. But in context, it could refer to:

• rainwater
• leaking water
• spilled water
• dampness from some earlier event

Vietnamese often leaves that kind of detail unstated if the situation is already clear. So the exact kind of water usually comes from context, not from the word nước alone.

Yes, but the nuance may shift a little.

• Nước hôm qua không hề thấm vào tường.
  This sounds like the water from yesterday did not seep into the wall.

• Hôm qua, nước không hề thấm vào tường.
  This sounds more like Yesterday, the water did not seep into the wall.

So both are possible, but your original sentence ties hôm qua more closely to nước.

It is understandable, but whether it sounds fully natural depends on the context.

If the intended meaning is Yesterday, the water did not seep into the wall at all, many speakers would prefer:

• Hôm qua, nước không hề thấm vào tường.

If the intended meaning is The water from yesterday did not seep into the wall at all, your original sentence works better.

So the sentence is grammatical, but a native speaker might choose a different word order depending on what exactly they want to emphasize.

A simple breakdown is:

• Nước hôm qua = subject noun phrase
• không hề = strong negation
• thấm vào = verb phrase
• tường = object/location target

So the pattern is roughly:

[subject] + [negation] + [verb] + [destination]

That gives:

Nước hôm qua + không hề + thấm vào + tường

This is a very common Vietnamese sentence pattern.