Đợi một giây.

Yes. In Vietnamese, it is very common to leave out the subject when it is obvious from context. Here, Đợi một giây. is an imperative, so the listener is understood automatically.

In natural English, it corresponds to:

• Wait a second.
• Hold on a second.

If you want to make the listener explicit, you can add a pronoun, for example:

• Anh đợi một giây.
• Chị đợi một giây.
• Em đợi một giây.

The exact pronoun depends on the relationship, age, and social context.

Đợi means to wait.

It is very close in meaning to chờ, which also means to wait. In many everyday situations, they can be used interchangeably:

• Đợi một giây.
• Chờ một giây.

Both can mean Wait a second.

That said, learners will often hear chờ a lot in speech, and đợi can sometimes sound a little more direct depending on context. The difference is not huge here, so both are useful to know.

Yes. Một literally means one.

In một giây, it means one second, just like English a second or one second.

So the structure is very straightforward:

• đợi = wait
• một = one
• giây = second

Together: wait one second

In casual English, we often translate that more naturally as wait a second rather than wait one second.

Here, giây means second as a unit of time.

So:

• một giây = one second

Be careful: Vietnamese has many short words that look similar, but here giây is specifically the time unit.

You may also hear more natural everyday alternatives such as:

• một chút = a little bit / a moment
• một lát = a little while
• một xíu = a tiny moment, very casual

So native speakers often say:

• Đợi một chút.
• Chờ một lát.
• Đợi một xíu.

These are often more natural than the literal one second.

A rough guide is:

• đợi: sounds roughly like duh-ee with a falling-glottal kind of tone
• một: roughly moht with a heavy low tone
• giây: roughly zây in the North, yây in much of the South

A few important pronunciation points:

• đ is like an English d, not like plain Vietnamese d
• ợi has the hỏi tone, which dips and rises
• một has the nặng tone, which is short and heavy
• giây has the level ngang tone

Regional pronunciation matters especially for gi:

• Northern: often like z
• Southern: often like y

So giây may sound like:

• Northern: zây
• Southern: yây

Yes, it is understandable and natural enough, but in real conversation Vietnamese speakers often prefer slightly softer or more conversational versions.

Very common alternatives are:

• Đợi một chút.
• Chờ một chút.
• Đợi xíu.
• Chờ tí.

These often sound more natural than the very literal wait one second, especially if you do not mean an actual exact second.

So Đợi một giây. is fine, but if you want to sound more everyday and less literal, Đợi một chút. is often better.

By itself, Đợi một giây. can sound a bit direct, depending on who you say it to and your tone of voice.

Vietnamese often adds softening words to make requests friendlier, such as:

• nhé
• đã
• với

Examples:

• Đợi một giây nhé.
• Chờ một chút nhé.
• Đợi em một giây nhé.

These sound softer and more natural in many situations.

If you are speaking to someone older, higher-status, or in a formal situation, it is usually better to include the appropriate pronoun and perhaps a softener.

No, that would not sound right.

You need something before giây here, because giây is a countable time unit. So you would normally say:

• một giây = one second
• hai giây = two seconds
• vài giây = a few seconds

So:

• Đợi một giây. = correct
• Đợi vài giây. = also correct
• Đợi giây. = not natural

The word order is very simple and mirrors the meaning closely:

• Đợi = wait
• một giây = one second

So the pattern is:

verb + amount of time

This is common in Vietnamese:

• Đợi một phút. = Wait a minute.
• Chờ một lát. = Wait a moment.
• Nghỉ một chút. = Rest a bit.

So if you know this sentence, you can easily build similar ones.

Yes, depending on context.

Possible natural translations include:

• Wait a second.
• Hold on a second.
• Just a second.

If the speaker is asking someone to pause, Wait a second is a good translation.

If the speaker means Please give me a moment, English might prefer:

• Just a second.
• One second.
• Hold on.

So the best translation depends on tone and situation, not just the individual words.

A few very useful ones are:

• Đợi một chút. = Wait a moment.
• Chờ một chút. = Wait a moment.
• Đợi tí. = Wait a sec.
• Đợi xíu. = Wait a sec. very casual
• Chờ em một chút. = Wait for me a moment.
• Đợi tôi một giây. = Wait for me a second. more explicit

These will help you sound more natural in everyday conversation than only using Đợi một giây.