Giá đã xuống.

It can mean any of those, depending on context.

In Vietnamese, giá is a noun meaning price. But Vietnamese often does not mark singular/plural or use articles the way English does, so:

• Giá đã xuống can mean The price has gone down
• It can also mean Prices have gone down
• In a broader context, it can even mean The price level has dropped

So you should rely on context, not just the single word.

đã marks that the change has already happened or is completed relative to the current reference point.

So in Giá đã xuống, đã helps give the sense of:

• has gone down
• went down
• already went down

It is not exactly the same as an English past tense marker. It is better thought of as an aspect marker showing that the event is completed.

No. That is a very common beginner misunderstanding.

đã often points to something completed, and this frequently lines up with the past in English, but it is not simply a past-tense word.

For example, it can mean something like:

• already
• by that time
• completed

So in this sentence, đã does not just mean past. It means the dropping has already occurred.

xuống literally means down or to go down.

In this sentence, it expresses a downward change. With giá, it means:

• to go down
• to drop
• to fall

So Giá đã xuống literally feels like Price already down/went down, which English naturally renders as The price has gone down or Prices have dropped.

It is functioning as the main predicate meaning go down / decrease.

Vietnamese often uses words that originally describe direction, such as lên and xuống, in extended meanings:

• lên = up, increase, rise
• xuống = down, decrease, fall

So here xuống is not about physical motion only. It is being used metaphorically for a decrease in price.

Because Vietnamese typically follows a pattern like:

subject/topic + aspect marker + predicate

So here:

• Giá = the subject/topic
• đã = completed aspect marker
• xuống = predicate meaning go down / drop

English needs an auxiliary structure like has gone down, but Vietnamese does not. It can express the idea much more directly.

Because Vietnamese does not build tense the way English does.

English uses forms like:

• has gone down
• went down
• had gone down

Vietnamese usually uses context and particles like đã, đang, sẽ, rồi, etc., rather than changing the verb or adding a direct equivalent of has.

So đã is helping express the completed meaning that English often shows with has.

Vietnamese does not normally use articles like a, an, and the.

That means giá by itself can mean:

• a price
• the price
• price
• prices

The exact meaning depends on context.

So Giá đã xuống is perfectly normal even though it has no separate word for the.

Yes. It is short, natural, and completely understandable.

It sounds especially normal in contexts like:

• conversation
• market talk
• business talk
• headlines
• quick updates

Vietnamese often prefers concise sentences like this when the context is already clear.

Both are natural, and both can mean The price has gone down.

The difference is mainly in nuance:

• Giá đã xuống: focuses on the fact that the decrease has occurred
• Giá xuống rồi: sounds very conversational and often emphasizes already / now it has happened

You may also hear:

• Giá đã xuống rồi

That adds even stronger completion, something like The price has already gone down.

Yes, absolutely.

giảm means decrease / decline / reduce, so:

• Giá đã giảm = The price has decreased
• Giá đã xuống = The price has gone down

The difference is mostly style:

• xuống is very everyday and intuitive
• giảm is a bit more formal or technical

Both are common and correct.

It can be either.

If people are already talking about one product, then it likely means:

• That item's price has gone down

If the topic is the market more generally, it may mean:

• Prices have gone down
• The general price level has dropped

Again, context tells you which reading is intended.

A rough learner-friendly guide is:

• Giá: starts like z in Northern Vietnamese, often more like y/j in Southern Vietnamese, with a rising tone
• đã: starts with a firm d sound like English d, with the ngã tone in Northern speech
• xuống: starts with s-like x, and has a rising tone

A very rough approximation for English speakers might be:

• zya / ya
• da
• soo-ong with the right Vietnamese vowel and tone

But tone and vowel quality matter a lot, so the best approach is to learn it from audio rather than English spelling.

Yes, very often.

xuống is widely used for decreases or downward movement, for example:

• nhiệt độ xuống = the temperature goes down
• huyết áp xuống = blood pressure goes down
• giọng xuống = the voice lowers
• đi xuống = go down physically

So in Giá đã xuống, it fits a very common Vietnamese pattern for describing a drop or decrease.