Rễ ở dưới đất.

A simple breakdown is:

• rễ = root / roots
• ở = to be at / to be located
• dưới = under / below
• đất = ground / soil / earth

So the structure is basically:

subject + location verb + place

→ Rễ + ở + dưới đất
→ Roots + are located + under the ground

Ở is commonly used to show location, like be at or be in.

In this sentence, it links rễ with its location:

• Rễ ở dưới đất = The roots are under the ground

Without ở, the sentence may still be understandable in some contexts, but ở makes the location relationship clear and natural.

Compare:

• Con mèo ở trên bàn = The cat is on the table
• Sách ở trong túi = The book is in the bag

So here, ở works like a location marker.

Yes, it functions as a location phrase.

• dưới = under / below
• đất = ground / soil

Together, dưới đất means under the ground or below the ground in this context.

Be careful: in other contexts, dưới đất can sometimes mean on the ground / down on the ground depending on what is being discussed. But with rễ, the intended meaning is naturally under the soil.

Vietnamese usually does not use articles like a, an, or the the way English does.

So rễ can mean:

• a root
• the root
• roots
• the roots

The exact meaning depends on context.

In a general statement about plants, Rễ ở dưới đất is understood as something like:

• Roots are underground
• The roots are under the ground

Vietnamese relies much more on context than English for this.

By itself, rễ does not show singular or plural.

It can mean:

• root
• roots

Context tells you which one is intended.

If you want to be more specific, Vietnamese can add words such as:

• một cái rễ = one root
• những rễ... or more naturally những cái rễ... = roots
• rễ cây = plant roots / the roots of a plant

But in a simple general sentence like Rễ ở dưới đất, it is fine to leave it unmarked.

Rễ can be tricky for English speakers because of both the initial consonant and the tone.

Main points:

• r in southern Vietnamese is often like an English r
• in northern Vietnamese, r is different and may sound more like a rolled or fricative sound, depending on accent
• ễ has a tone mark and a vowel shape that English does not have exactly

The tone on rễ is the ngã tone in standard spelling. In practice, its exact sound varies by dialect.

A rough learner-friendly approach:

• aim for something like reh with a marked Vietnamese tone
• listen to native audio if possible, because tones matter a lot more than English speakers usually expect

The safest advice: learn it as a full word from audio, not just from roman letters.

Actually, the word order is fairly similar to English once you understand the parts.

Vietnamese:

• Rễ = subject
• ở = is/are located
• dưới đất = under the ground

English:

• The roots
  • are
    • under the ground

So the pattern is not very different. What feels different is that Vietnamese:

• does not use articles like the
• does not mark plural here
• often uses a location verb like ở

You may hear shortened expressions in conversation, but Rễ ở dưới đất is the clearer and more standard full sentence.

Using ở is especially helpful for learners because it clearly marks location.

So:

• Rễ ở dưới đất = good, clear, natural
• Rễ dưới đất = possible in some contexts, but less complete

As a learner, it is better to keep ở.

Yes, and the nuance is a little different.

• dưới đất = under the ground
• trong đất = in the soil / in the ground

For roots, both can make sense:

• Rễ ở dưới đất = emphasizes that the roots are below ground
• Rễ ở trong đất = emphasizes that the roots are in the soil

Both are natural, but they are not exactly identical in feeling.

Yes, it is natural and easy to understand.

That said, native speakers might also say:

• Rễ cây ở dưới đất = The roots of the plant are under the ground
• Rễ cây nằm dưới đất = The roots lie underground
• Rễ ở trong đất = Roots are in the soil

Your original sentence is simple and correct, especially for basic learning.

Đất is a very common word with several related meanings:

• earth
• ground
• soil
• land

In Rễ ở dưới đất, it most naturally means ground/soil.

So this is not about land in the sense of property, but the earth or soil where roots grow.

Not in this sentence.

Classifiers are often used with nouns when you are counting or specifying them, but they are not required in every sentence.

For example:

• một cái rễ = one root
• cái rễ này = this root

But in a general statement like Rễ ở dưới đất, no classifier is needed.

Yes. Vietnamese often uses a bare noun like rễ to make a general statement.

So Rễ ở dưới đất can sound like:

• Roots are underground
• Roots are under the ground

This kind of article-free, number-free wording is very common when stating general facts.