Họ phá kế hoạch.

Họ usually means they or them, depending on position in the sentence. In Họ phá kế hoạch, it is the subject, so it means they.

Vietnamese pronouns do not work exactly like English ones. Họ is a fairly neutral written/spoken way to say they, especially for a group of people.

Vietnamese usually follows Subject + Verb + Object, just like English.

So here:

• Họ = subject
• phá = verb
• kế hoạch = object

That is why Họ phá kế hoạch lines up neatly with They ruin the plan or They destroy the plan.

Phá often means to break, to destroy, to ruin, or to spoil, depending on context.

With kế hoạch meaning plan, phá kế hoạch usually means something like:

• ruin the plan
• wreck the plan
• sabotage the plan
• spoil the plan

So the idea is not necessarily physically destroying something. It can also mean causing a plan to fail.

Vietnamese does not have articles like a, an, and the in the same way English does.

So kế hoạch can mean:

• a plan
• the plan
• sometimes just plan/plans in a general sense

The exact meaning depends on context. In many short example sentences, English may translate it as the plan, but Vietnamese does not need a separate word for that.

Not here. Kế hoạch is a noun meaning plan, and it can appear directly after the verb.

Classifiers are often used with numbers or demonstratives, for example when you want to say something like:

• một kế hoạch = a plan
• kế hoạch này = this plan

In Họ phá kế hoạch, no classifier is required.

By itself, Vietnamese verbs do not change form for tense the way English verbs do.

So Họ phá kế hoạch could refer to different times depending on context:

• they ruin the plan
• they ruined the plan
• they are ruining the plan

If Vietnamese wants to make time clearer, it often adds time words or aspect markers, such as:

• đã for past: Họ đã phá kế hoạch = They ruined the plan
• đang for ongoing action: Họ đang phá kế hoạch = They are ruining the plan
• sẽ for future: Họ sẽ phá kế hoạch = They will ruin the plan

Yes. Họ is gender-neutral. It can refer to:

• a group of men
• a group of women
• a mixed group

Vietnamese does not need different plural subject pronouns like they for different genders.

Yes, it is natural, but the exact nuance depends on context.

Phá kế hoạch suggests ruining or wrecking a plan. In some situations, Vietnamese might also use other verbs, depending on what exactly happened:

• hủy kế hoạch = cancel the plan
• làm hỏng kế hoạch = mess up the plan / make the plan fail
• phá hoại kế hoạch = sabotage the plan or deliberately damage the plan

So phá kế hoạch is understandable and natural, especially if the idea is that someone interferes with or ruins a plan.

Vietnamese is a tonal language, so tone is part of the word itself.

• kế hoạch is approximately pronounced like kay hoahk, but with proper Vietnamese vowels and tones.
• kế has the sắc tone.
• hoạch has a heavy/falling checked tone.

The tones matter because changing them can create a different word or make the word hard to understand. So when learning this sentence, it is important to learn not just the consonants and vowels, but also the tones.

You usually put không before the verb:

• Họ không phá kế hoạch.

That means They do not ruin the plan or They didn’t ruin the plan, depending on context.

If you want a clearly past negative, you might say:

• Họ đã không phá kế hoạch. = They did not ruin the plan.

Yes. Vietnamese pronouns depend a lot on relationship, age, and social context. Instead of họ, speakers might use other words if the situation is more specific.

For example:

• bọn họ = they / those people
• mấy người đó = those people
• a kinship term used as a pronoun in context

But họ is a good neutral form, especially in simple example sentences or written Vietnamese.