Kế hoạch của chúng tôi thay đổi vì chị tôi phải đón em ở trường.

In Vietnamese, possession usually comes after the noun.

So:

• kế hoạch = plan
• kế hoạch của chúng tôi = our plan / the plan of ours

This is a very common pattern:

• nhà của tôi = my house
• xe của anh ấy = his car

So Vietnamese often expresses our plan as kế hoạch của chúng tôi, not by putting the possessor first like in English.

Chúng tôi means we/us, but it usually does not include the listener.

By contrast, chúng ta usually does include the listener.

So:

• chúng tôi = we, not you
• chúng ta = we, including you

In this sentence, kế hoạch của chúng tôi means our plan, but probably not the listener’s plan.

Vietnamese verbs do not change form the way English verbs do.

• thay đổi can mean change, changed, or will change
• the time is understood from context or from time words

So in this sentence, thay đổi is interpreted as changed because the situation makes that meaning clear.

Vietnamese often leaves tense unmarked when the meaning is already obvious.

Yes. In this sentence, thay đổi functions as a verb meaning to change.

So:

• Kế hoạch của chúng tôi thay đổi = Our plan changed

Depending on context, thay đổi can also behave like an adjective-like predicate, but for a learner, it is easiest to understand it here as the main verb change.

Vì means because.

It introduces the reason:

• Kế hoạch của chúng tôi thay đổi = Our plan changed
• vì chị tôi phải đón em ở trường = because my older sister had to pick up my younger sibling at school

So vì links the result and the cause, just like because in English.

Phải means must, have to, or need to.

So:

• chị tôi phải đón em = my older sister has to pick up my younger sibling

It shows obligation or necessity.

A few examples:

• Tôi phải đi. = I have to go.
• Anh ấy phải làm việc. = He has to work.

Vietnamese often prefers family relationship words when talking about people, especially relatives.

• chị = older sister
• chị tôi = my older sister

Using cô ấy would just mean she, but chị tôi gives the exact relationship. Vietnamese commonly does this because kinship terms are very important in everyday speech.

Chị means older sister or older female person, depending on context.

In chị tôi, it clearly means my older sister.

Important: chị tells you that this person is:

• female
• older than the speaker in the relevant family/social relationship

So Vietnamese gives relationship information that English often leaves out.

Here, em most likely means a younger sibling, probably the speaker’s younger brother or sister.

Because the sentence already has chị tôi = my older sister, em naturally suggests a younger sibling in the family.

But em is broader than one English word. It can mean:

• younger sibling
• younger person
• a way to refer to yourself when speaking to someone older
• a way to address someone younger

So the exact English translation depends heavily on context.

No. Em does not tell you the gender.

It only tells you that the person is younger in the relationship.

So em could refer to:

• younger brother
• younger sister

If Vietnamese speakers want to be more specific, they can add words like:

• em trai = younger brother
• em gái = younger sister

Đón here means to pick someone up or to go meet someone when they arrive/finish.

So:

• đón em ở trường = pick up my younger sibling at school

This verb is very common for picking someone up from school, the airport, the station, and so on.

Examples:

• đón con ở trường = pick up the child at school
• đón bạn ở sân bay = pick up a friend at the airport

The structure is:

• đón = pick up
• em = the person being picked up
• ở trường = at school

So the order is:

verb + object + location

That is very normal in Vietnamese.

Compare:

• đón em ở trường = pick up my younger sibling at school
• gặp bạn ở quán cà phê = meet a friend at the café

Ở means at/in, and trường means school.

So ở trường means at school.

In this sentence, it tells the location where the pickup happens:

• đón em ở trường = pick up the younger sibling at school

By itself, kế hoạch is not clearly marked for singular or plural. Vietnamese nouns usually do not change form for number.

So kế hoạch của chúng tôi could theoretically mean:

• our plan
• our plans

But in this sentence, the most natural interpretation is usually our plan in the singular.

Number in Vietnamese often comes from context rather than noun endings.

Vietnamese does not use articles the same way English does.

So kế hoạch can mean:

• a plan
• the plan
• plans

depending on context.

That is why kế hoạch của chúng tôi can naturally be translated as our plan without needing a separate word for the.

In some contexts, em can refer to me, but in this sentence that reading is less likely.

Because the speaker says chị tôi = my older sister, em most naturally refers to a younger sibling in the family, not the speaker.

Still, Vietnamese pronouns depend heavily on relationship and context, so learners should remember that words like em do not map perfectly to just one English pronoun.

Mostly, yes.

The sentence follows this general order:

• Kế hoạch của chúng tôi = our plan
• thay đổi = changed
• vì = because
• chị tôi = my older sister
• phải đón em ở trường = had to pick up my younger sibling at school

So it is broadly:

subject + verb + because + subject + verb phrase

That makes this sentence relatively straightforward for English speakers, even though some details, like kinship terms and possession, work differently.