Kỹ thuật viên đã rời đi.

Kỹ thuật viên is a noun phrase meaning technician.

It is made of:

• kỹ thuật = technique, technology, technical skill
• viên = a person working in a role, often seen in job titles

So kỹ thuật viên literally means something like technical worker/staff member, but in natural English it is usually just technician.

In Vietnamese, it is written as three separate syllables, but together they function as one job title.

Đã marks that the action happened in the past or is completed.

In Kỹ thuật viên đã rời đi, đã tells you the leaving already happened.

For English speakers, it often feels similar to:

• the past tense
• or sometimes already, depending on context

But it is not exactly the same as English tense. Vietnamese does not change the verb form the way English does. Instead, it often uses words like đã, đang, and sẽ to show time or aspect.

Not always.

In many sentences, đã mainly shows past/completed action, not necessarily the strong English sense of already.

So in this sentence, đã rời đi most naturally means left or has left, depending on context.

If you want to strongly emphasize already, Vietnamese often uses rồi:

• Kỹ thuật viên rời đi rồi.
• Kỹ thuật viên đã rời đi rồi.

Both can suggest The technician has already left.

Rời đi means to leave / to depart, and it sounds a bit more explicit than just đi.

• đi = go
• rời = leave, depart from
• rời đi = leave, go away, depart

Using rời đi makes it very clear that the person left the place.

If you said:

• Kỹ thuật viên đã đi.

that can also mean The technician left, and it is very natural in conversation. But rời đi can sound a little more formal or deliberate.

Yes, you can.

Vietnamese often leaves time markers out if the context already makes the timing clear.

• Kỹ thuật viên rời đi. = The technician leaves / left / has left, depending on context
• Kỹ thuật viên đã rời đi. = more clearly marks the action as past/completed

So đã is helpful when you want to remove ambiguity.

The word order is:

Subject + time/aspect marker + verb

So:

• Kỹ thuật viên = subject
• đã = past/completed marker
• rời đi = verb phrase

This is very common Vietnamese sentence structure.

Unlike English, the verb itself does not change form. The time reference is shown by separate words like đã.

By itself, kỹ thuật viên can be understood as singular or generic, depending on context.

In this sentence, it will usually be understood as the technician or a technician.

Vietnamese nouns do not automatically show singular/plural the way English often does. If you need to be specific, you can add words such as:

• một kỹ thuật viên = one / a technician
• các kỹ thuật viên = technicians
• những kỹ thuật viên = technicians

So the sentence does not grammatically force singular or plural, but context usually makes it clear.

Vietnamese does not use articles like English a and the in the same way.

So kỹ thuật viên can mean:

• a technician
• the technician
• sometimes technicians in a general sense

The exact meaning depends on context.

If you want to be more specific, Vietnamese can use other words:

• một kỹ thuật viên = a technician
• người kỹ thuật viên đó = that technician
• kỹ thuật viên này = this technician

A common way is to put không before the verb:

Kỹ thuật viên đã không rời đi.

This means The technician did not leave.

In everyday Vietnamese, people may also say:

• Kỹ thuật viên không rời đi.

If the past is already clear from context, đã may be omitted.

A very common yes/no question pattern is to add chưa at the end:

Kỹ thuật viên đã rời đi chưa?

This means Has the technician left yet?

A typical answer would be:

• Rồi. = Yes / Already.
• Chưa. = Not yet.

You could also ask more neutrally with intonation in speech, but đã ... chưa? is one of the most useful patterns to learn.

It can be used by itself, but very often it appears in combinations such as:

• rời đi = leave
• rời khỏi = leave, depart from
• rời xa = leave behind / move away from

So rời đi is a very natural combination.

For example:

• Anh ấy rời đi lúc 5 giờ. = He left at 5 o’clock.
• Cô ấy rời khỏi văn phòng. = She left the office.

A rough pronunciation guide is:

Kỹ thuật viên đã rời đi
≈ kee thwut vee-en da roy dee

A few notes:

• kỹ has a dipping-rising tone in standard Northern Vietnamese
• thuật ends with a final t, so it is short and clipped
• viên sounds roughly like vee-en
• đã sounds somewhat like za in the North and ya in many Southern accents
• rời is roughly roy with the proper Vietnamese tone
• đi is like dee

The tones matter a lot in Vietnamese, so it is best to listen to a native recording if possible rather than rely only on English-style spelling.